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TOMOYO Linux Cross Reference
Linux/fs/aio.c

Version: ~ [ linux-6.12-rc7 ] ~ [ linux-6.11.7 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.60 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.116 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.171 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.229 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.285 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.323 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.12 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

Diff markup

Differences between /fs/aio.c (Version linux-6.12-rc7) and /fs/aio.c (Version linux-5.13.19)


  1 /*                                                  1 /*
  2  *      An async IO implementation for Linux        2  *      An async IO implementation for Linux
  3  *      Written by Benjamin LaHaise <bcrl@kvac      3  *      Written by Benjamin LaHaise <bcrl@kvack.org>
  4  *                                                  4  *
  5  *      Implements an efficient asynchronous i      5  *      Implements an efficient asynchronous io interface.
  6  *                                                  6  *
  7  *      Copyright 2000, 2001, 2002 Red Hat, In      7  *      Copyright 2000, 2001, 2002 Red Hat, Inc.  All Rights Reserved.
  8  *      Copyright 2018 Christoph Hellwig.           8  *      Copyright 2018 Christoph Hellwig.
  9  *                                                  9  *
 10  *      See ../COPYING for licensing terms.        10  *      See ../COPYING for licensing terms.
 11  */                                                11  */
 12 #define pr_fmt(fmt) "%s: " fmt, __func__           12 #define pr_fmt(fmt) "%s: " fmt, __func__
 13                                                    13 
 14 #include <linux/kernel.h>                          14 #include <linux/kernel.h>
 15 #include <linux/init.h>                            15 #include <linux/init.h>
 16 #include <linux/errno.h>                           16 #include <linux/errno.h>
 17 #include <linux/time.h>                            17 #include <linux/time.h>
 18 #include <linux/aio_abi.h>                         18 #include <linux/aio_abi.h>
 19 #include <linux/export.h>                          19 #include <linux/export.h>
 20 #include <linux/syscalls.h>                        20 #include <linux/syscalls.h>
 21 #include <linux/backing-dev.h>                     21 #include <linux/backing-dev.h>
 22 #include <linux/refcount.h>                        22 #include <linux/refcount.h>
 23 #include <linux/uio.h>                             23 #include <linux/uio.h>
 24                                                    24 
 25 #include <linux/sched/signal.h>                    25 #include <linux/sched/signal.h>
 26 #include <linux/fs.h>                              26 #include <linux/fs.h>
 27 #include <linux/file.h>                            27 #include <linux/file.h>
 28 #include <linux/mm.h>                              28 #include <linux/mm.h>
 29 #include <linux/mman.h>                            29 #include <linux/mman.h>
 30 #include <linux/percpu.h>                          30 #include <linux/percpu.h>
 31 #include <linux/slab.h>                            31 #include <linux/slab.h>
 32 #include <linux/timer.h>                           32 #include <linux/timer.h>
 33 #include <linux/aio.h>                             33 #include <linux/aio.h>
 34 #include <linux/highmem.h>                         34 #include <linux/highmem.h>
 35 #include <linux/workqueue.h>                       35 #include <linux/workqueue.h>
 36 #include <linux/security.h>                        36 #include <linux/security.h>
 37 #include <linux/eventfd.h>                         37 #include <linux/eventfd.h>
 38 #include <linux/blkdev.h>                          38 #include <linux/blkdev.h>
 39 #include <linux/compat.h>                          39 #include <linux/compat.h>
 40 #include <linux/migrate.h>                         40 #include <linux/migrate.h>
 41 #include <linux/ramfs.h>                           41 #include <linux/ramfs.h>
 42 #include <linux/percpu-refcount.h>                 42 #include <linux/percpu-refcount.h>
 43 #include <linux/mount.h>                           43 #include <linux/mount.h>
 44 #include <linux/pseudo_fs.h>                       44 #include <linux/pseudo_fs.h>
 45                                                    45 
 46 #include <linux/uaccess.h>                         46 #include <linux/uaccess.h>
 47 #include <linux/nospec.h>                          47 #include <linux/nospec.h>
 48                                                    48 
 49 #include "internal.h"                              49 #include "internal.h"
 50                                                    50 
 51 #define KIOCB_KEY               0                  51 #define KIOCB_KEY               0
 52                                                    52 
 53 #define AIO_RING_MAGIC                  0xa10a     53 #define AIO_RING_MAGIC                  0xa10a10a1
 54 #define AIO_RING_COMPAT_FEATURES        1          54 #define AIO_RING_COMPAT_FEATURES        1
 55 #define AIO_RING_INCOMPAT_FEATURES      0          55 #define AIO_RING_INCOMPAT_FEATURES      0
 56 struct aio_ring {                                  56 struct aio_ring {
 57         unsigned        id;     /* kernel inte     57         unsigned        id;     /* kernel internal index number */
 58         unsigned        nr;     /* number of i     58         unsigned        nr;     /* number of io_events */
 59         unsigned        head;   /* Written to      59         unsigned        head;   /* Written to by userland or under ring_lock
 60                                  * mutex by ai     60                                  * mutex by aio_read_events_ring(). */
 61         unsigned        tail;                      61         unsigned        tail;
 62                                                    62 
 63         unsigned        magic;                     63         unsigned        magic;
 64         unsigned        compat_features;           64         unsigned        compat_features;
 65         unsigned        incompat_features;         65         unsigned        incompat_features;
 66         unsigned        header_length;  /* siz     66         unsigned        header_length;  /* size of aio_ring */
 67                                                    67 
 68                                                    68 
 69         struct io_event         io_events[];       69         struct io_event         io_events[];
 70 }; /* 128 bytes + ring size */                     70 }; /* 128 bytes + ring size */
 71                                                    71 
 72 /*                                                 72 /*
 73  * Plugging is meant to work with larger batch     73  * Plugging is meant to work with larger batches of IOs. If we don't
 74  * have more than the below, then don't bother     74  * have more than the below, then don't bother setting up a plug.
 75  */                                                75  */
 76 #define AIO_PLUG_THRESHOLD      2                  76 #define AIO_PLUG_THRESHOLD      2
 77                                                    77 
 78 #define AIO_RING_PAGES  8                          78 #define AIO_RING_PAGES  8
 79                                                    79 
 80 struct kioctx_table {                              80 struct kioctx_table {
 81         struct rcu_head         rcu;               81         struct rcu_head         rcu;
 82         unsigned                nr;                82         unsigned                nr;
 83         struct kioctx __rcu     *table[] __cou !!  83         struct kioctx __rcu     *table[];
 84 };                                                 84 };
 85                                                    85 
 86 struct kioctx_cpu {                                86 struct kioctx_cpu {
 87         unsigned                reqs_available     87         unsigned                reqs_available;
 88 };                                                 88 };
 89                                                    89 
 90 struct ctx_rq_wait {                               90 struct ctx_rq_wait {
 91         struct completion comp;                    91         struct completion comp;
 92         atomic_t count;                            92         atomic_t count;
 93 };                                                 93 };
 94                                                    94 
 95 struct kioctx {                                    95 struct kioctx {
 96         struct percpu_ref       users;             96         struct percpu_ref       users;
 97         atomic_t                dead;              97         atomic_t                dead;
 98                                                    98 
 99         struct percpu_ref       reqs;              99         struct percpu_ref       reqs;
100                                                   100 
101         unsigned long           user_id;          101         unsigned long           user_id;
102                                                   102 
103         struct kioctx_cpu __percpu *cpu;       !! 103         struct __percpu kioctx_cpu *cpu;
104                                                   104 
105         /*                                        105         /*
106          * For percpu reqs_available, number o    106          * For percpu reqs_available, number of slots we move to/from global
107          * counter at a time:                     107          * counter at a time:
108          */                                       108          */
109         unsigned                req_batch;        109         unsigned                req_batch;
110         /*                                        110         /*
111          * This is what userspace passed to io    111          * This is what userspace passed to io_setup(), it's not used for
112          * anything but counting against the g    112          * anything but counting against the global max_reqs quota.
113          *                                        113          *
114          * The real limit is nr_events - 1, wh    114          * The real limit is nr_events - 1, which will be larger (see
115          * aio_setup_ring())                      115          * aio_setup_ring())
116          */                                       116          */
117         unsigned                max_reqs;         117         unsigned                max_reqs;
118                                                   118 
119         /* Size of ringbuffer, in units of str    119         /* Size of ringbuffer, in units of struct io_event */
120         unsigned                nr_events;        120         unsigned                nr_events;
121                                                   121 
122         unsigned long           mmap_base;        122         unsigned long           mmap_base;
123         unsigned long           mmap_size;        123         unsigned long           mmap_size;
124                                                   124 
125         struct folio            **ring_folios; !! 125         struct page             **ring_pages;
126         long                    nr_pages;         126         long                    nr_pages;
127                                                   127 
128         struct rcu_work         free_rwork;       128         struct rcu_work         free_rwork;     /* see free_ioctx() */
129                                                   129 
130         /*                                        130         /*
131          * signals when all in-flight requests    131          * signals when all in-flight requests are done
132          */                                       132          */
133         struct ctx_rq_wait      *rq_wait;         133         struct ctx_rq_wait      *rq_wait;
134                                                   134 
135         struct {                                  135         struct {
136                 /*                                136                 /*
137                  * This counts the number of a    137                  * This counts the number of available slots in the ringbuffer,
138                  * so we avoid overflowing it:    138                  * so we avoid overflowing it: it's decremented (if positive)
139                  * when allocating a kiocb and    139                  * when allocating a kiocb and incremented when the resulting
140                  * io_event is pulled off the     140                  * io_event is pulled off the ringbuffer.
141                  *                                141                  *
142                  * We batch accesses to it wit    142                  * We batch accesses to it with a percpu version.
143                  */                               143                  */
144                 atomic_t        reqs_available    144                 atomic_t        reqs_available;
145         } ____cacheline_aligned_in_smp;           145         } ____cacheline_aligned_in_smp;
146                                                   146 
147         struct {                                  147         struct {
148                 spinlock_t      ctx_lock;         148                 spinlock_t      ctx_lock;
149                 struct list_head active_reqs;     149                 struct list_head active_reqs;   /* used for cancellation */
150         } ____cacheline_aligned_in_smp;           150         } ____cacheline_aligned_in_smp;
151                                                   151 
152         struct {                                  152         struct {
153                 struct mutex    ring_lock;        153                 struct mutex    ring_lock;
154                 wait_queue_head_t wait;           154                 wait_queue_head_t wait;
155         } ____cacheline_aligned_in_smp;           155         } ____cacheline_aligned_in_smp;
156                                                   156 
157         struct {                                  157         struct {
158                 unsigned        tail;             158                 unsigned        tail;
159                 unsigned        completed_even    159                 unsigned        completed_events;
160                 spinlock_t      completion_loc    160                 spinlock_t      completion_lock;
161         } ____cacheline_aligned_in_smp;           161         } ____cacheline_aligned_in_smp;
162                                                   162 
163         struct folio            *internal_foli !! 163         struct page             *internal_pages[AIO_RING_PAGES];
164         struct file             *aio_ring_file    164         struct file             *aio_ring_file;
165                                                   165 
166         unsigned                id;               166         unsigned                id;
167 };                                                167 };
168                                                   168 
169 /*                                                169 /*
170  * First field must be the file pointer in all    170  * First field must be the file pointer in all the
171  * iocb unions! See also 'struct kiocb' in <li    171  * iocb unions! See also 'struct kiocb' in <linux/fs.h>
172  */                                               172  */
173 struct fsync_iocb {                               173 struct fsync_iocb {
174         struct file             *file;            174         struct file             *file;
175         struct work_struct      work;             175         struct work_struct      work;
176         bool                    datasync;         176         bool                    datasync;
177         struct cred             *creds;           177         struct cred             *creds;
178 };                                                178 };
179                                                   179 
180 struct poll_iocb {                                180 struct poll_iocb {
181         struct file             *file;            181         struct file             *file;
182         struct wait_queue_head  *head;            182         struct wait_queue_head  *head;
183         __poll_t                events;           183         __poll_t                events;
                                                   >> 184         bool                    done;
184         bool                    cancelled;        185         bool                    cancelled;
185         bool                    work_scheduled << 
186         bool                    work_need_resc << 
187         struct wait_queue_entry wait;             186         struct wait_queue_entry wait;
188         struct work_struct      work;             187         struct work_struct      work;
189 };                                                188 };
190                                                   189 
191 /*                                                190 /*
192  * NOTE! Each of the iocb union members has th    191  * NOTE! Each of the iocb union members has the file pointer
193  * as the first entry in their struct definiti    192  * as the first entry in their struct definition. So you can
194  * access the file pointer through any of the     193  * access the file pointer through any of the sub-structs,
195  * or directly as just 'ki_filp' in this struc    194  * or directly as just 'ki_filp' in this struct.
196  */                                               195  */
197 struct aio_kiocb {                                196 struct aio_kiocb {
198         union {                                   197         union {
199                 struct file             *ki_fi    198                 struct file             *ki_filp;
200                 struct kiocb            rw;       199                 struct kiocb            rw;
201                 struct fsync_iocb       fsync;    200                 struct fsync_iocb       fsync;
202                 struct poll_iocb        poll;     201                 struct poll_iocb        poll;
203         };                                        202         };
204                                                   203 
205         struct kioctx           *ki_ctx;          204         struct kioctx           *ki_ctx;
206         kiocb_cancel_fn         *ki_cancel;       205         kiocb_cancel_fn         *ki_cancel;
207                                                   206 
208         struct io_event         ki_res;           207         struct io_event         ki_res;
209                                                   208 
210         struct list_head        ki_list;          209         struct list_head        ki_list;        /* the aio core uses this
211                                                   210                                                  * for cancellation */
212         refcount_t              ki_refcnt;        211         refcount_t              ki_refcnt;
213                                                   212 
214         /*                                        213         /*
215          * If the aio_resfd field of the users    214          * If the aio_resfd field of the userspace iocb is not zero,
216          * this is the underlying eventfd cont    215          * this is the underlying eventfd context to deliver events to.
217          */                                       216          */
218         struct eventfd_ctx      *ki_eventfd;      217         struct eventfd_ctx      *ki_eventfd;
219 };                                                218 };
220                                                   219 
221 /*------ sysctl variables----*/                   220 /*------ sysctl variables----*/
222 static DEFINE_SPINLOCK(aio_nr_lock);              221 static DEFINE_SPINLOCK(aio_nr_lock);
223 static unsigned long aio_nr;            /* cur !! 222 unsigned long aio_nr;           /* current system wide number of aio requests */
224 static unsigned long aio_max_nr = 0x10000; /*  !! 223 unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
225 /*----end sysctl variables---*/                   224 /*----end sysctl variables---*/
226 #ifdef CONFIG_SYSCTL                           << 
227 static struct ctl_table aio_sysctls[] = {      << 
228         {                                      << 
229                 .procname       = "aio-nr",    << 
230                 .data           = &aio_nr,     << 
231                 .maxlen         = sizeof(aio_n << 
232                 .mode           = 0444,        << 
233                 .proc_handler   = proc_doulong << 
234         },                                     << 
235         {                                      << 
236                 .procname       = "aio-max-nr" << 
237                 .data           = &aio_max_nr, << 
238                 .maxlen         = sizeof(aio_m << 
239                 .mode           = 0644,        << 
240                 .proc_handler   = proc_doulong << 
241         },                                     << 
242 };                                             << 
243                                                << 
244 static void __init aio_sysctl_init(void)       << 
245 {                                              << 
246         register_sysctl_init("fs", aio_sysctls << 
247 }                                              << 
248 #else                                          << 
249 #define aio_sysctl_init() do { } while (0)     << 
250 #endif                                         << 
251                                                   225 
252 static struct kmem_cache        *kiocb_cachep;    226 static struct kmem_cache        *kiocb_cachep;
253 static struct kmem_cache        *kioctx_cachep    227 static struct kmem_cache        *kioctx_cachep;
254                                                   228 
255 static struct vfsmount *aio_mnt;                  229 static struct vfsmount *aio_mnt;
256                                                   230 
257 static const struct file_operations aio_ring_f    231 static const struct file_operations aio_ring_fops;
258 static const struct address_space_operations a    232 static const struct address_space_operations aio_ctx_aops;
259                                                   233 
260 static struct file *aio_private_file(struct ki    234 static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
261 {                                                 235 {
262         struct file *file;                        236         struct file *file;
263         struct inode *inode = alloc_anon_inode    237         struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
264         if (IS_ERR(inode))                        238         if (IS_ERR(inode))
265                 return ERR_CAST(inode);           239                 return ERR_CAST(inode);
266                                                   240 
267         inode->i_mapping->a_ops = &aio_ctx_aop    241         inode->i_mapping->a_ops = &aio_ctx_aops;
268         inode->i_mapping->i_private_data = ctx !! 242         inode->i_mapping->private_data = ctx;
269         inode->i_size = PAGE_SIZE * nr_pages;     243         inode->i_size = PAGE_SIZE * nr_pages;
270                                                   244 
271         file = alloc_file_pseudo(inode, aio_mn    245         file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
272                                 O_RDWR, &aio_r    246                                 O_RDWR, &aio_ring_fops);
273         if (IS_ERR(file))                         247         if (IS_ERR(file))
274                 iput(inode);                      248                 iput(inode);
275         return file;                              249         return file;
276 }                                                 250 }
277                                                   251 
278 static int aio_init_fs_context(struct fs_conte    252 static int aio_init_fs_context(struct fs_context *fc)
279 {                                                 253 {
280         if (!init_pseudo(fc, AIO_RING_MAGIC))     254         if (!init_pseudo(fc, AIO_RING_MAGIC))
281                 return -ENOMEM;                   255                 return -ENOMEM;
282         fc->s_iflags |= SB_I_NOEXEC;              256         fc->s_iflags |= SB_I_NOEXEC;
283         return 0;                                 257         return 0;
284 }                                                 258 }
285                                                   259 
286 /* aio_setup                                      260 /* aio_setup
287  *      Creates the slab caches used by the ai    261  *      Creates the slab caches used by the aio routines, panic on
288  *      failure as this is done early during t    262  *      failure as this is done early during the boot sequence.
289  */                                               263  */
290 static int __init aio_setup(void)                 264 static int __init aio_setup(void)
291 {                                                 265 {
292         static struct file_system_type aio_fs     266         static struct file_system_type aio_fs = {
293                 .name           = "aio",          267                 .name           = "aio",
294                 .init_fs_context = aio_init_fs    268                 .init_fs_context = aio_init_fs_context,
295                 .kill_sb        = kill_anon_su    269                 .kill_sb        = kill_anon_super,
296         };                                        270         };
297         aio_mnt = kern_mount(&aio_fs);            271         aio_mnt = kern_mount(&aio_fs);
298         if (IS_ERR(aio_mnt))                      272         if (IS_ERR(aio_mnt))
299                 panic("Failed to create aio fs    273                 panic("Failed to create aio fs mount.");
300                                                   274 
301         kiocb_cachep = KMEM_CACHE(aio_kiocb, S    275         kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
302         kioctx_cachep = KMEM_CACHE(kioctx,SLAB    276         kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
303         aio_sysctl_init();                     << 
304         return 0;                                 277         return 0;
305 }                                                 278 }
306 __initcall(aio_setup);                            279 __initcall(aio_setup);
307                                                   280 
308 static void put_aio_ring_file(struct kioctx *c    281 static void put_aio_ring_file(struct kioctx *ctx)
309 {                                                 282 {
310         struct file *aio_ring_file = ctx->aio_    283         struct file *aio_ring_file = ctx->aio_ring_file;
311         struct address_space *i_mapping;          284         struct address_space *i_mapping;
312                                                   285 
313         if (aio_ring_file) {                      286         if (aio_ring_file) {
314                 truncate_setsize(file_inode(ai    287                 truncate_setsize(file_inode(aio_ring_file), 0);
315                                                   288 
316                 /* Prevent further access to t    289                 /* Prevent further access to the kioctx from migratepages */
317                 i_mapping = aio_ring_file->f_m    290                 i_mapping = aio_ring_file->f_mapping;
318                 spin_lock(&i_mapping->i_privat !! 291                 spin_lock(&i_mapping->private_lock);
319                 i_mapping->i_private_data = NU !! 292                 i_mapping->private_data = NULL;
320                 ctx->aio_ring_file = NULL;        293                 ctx->aio_ring_file = NULL;
321                 spin_unlock(&i_mapping->i_priv !! 294                 spin_unlock(&i_mapping->private_lock);
322                                                   295 
323                 fput(aio_ring_file);              296                 fput(aio_ring_file);
324         }                                         297         }
325 }                                                 298 }
326                                                   299 
327 static void aio_free_ring(struct kioctx *ctx)     300 static void aio_free_ring(struct kioctx *ctx)
328 {                                                 301 {
329         int i;                                    302         int i;
330                                                   303 
331         /* Disconnect the kiotx from the ring     304         /* Disconnect the kiotx from the ring file.  This prevents future
332          * accesses to the kioctx from page mi    305          * accesses to the kioctx from page migration.
333          */                                       306          */
334         put_aio_ring_file(ctx);                   307         put_aio_ring_file(ctx);
335                                                   308 
336         for (i = 0; i < ctx->nr_pages; i++) {     309         for (i = 0; i < ctx->nr_pages; i++) {
337                 struct folio *folio = ctx->rin !! 310                 struct page *page;
338                                                !! 311                 pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
339                 if (!folio)                    !! 312                                 page_count(ctx->ring_pages[i]));
                                                   >> 313                 page = ctx->ring_pages[i];
                                                   >> 314                 if (!page)
340                         continue;                 315                         continue;
341                                                !! 316                 ctx->ring_pages[i] = NULL;
342                 pr_debug("pid(%d) [%d] folio-> !! 317                 put_page(page);
343                          folio_ref_count(folio << 
344                 ctx->ring_folios[i] = NULL;    << 
345                 folio_put(folio);              << 
346         }                                         318         }
347                                                   319 
348         if (ctx->ring_folios && ctx->ring_foli !! 320         if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
349                 kfree(ctx->ring_folios);       !! 321                 kfree(ctx->ring_pages);
350                 ctx->ring_folios = NULL;       !! 322                 ctx->ring_pages = NULL;
351         }                                         323         }
352 }                                                 324 }
353                                                   325 
354 static int aio_ring_mremap(struct vm_area_stru    326 static int aio_ring_mremap(struct vm_area_struct *vma)
355 {                                                 327 {
356         struct file *file = vma->vm_file;         328         struct file *file = vma->vm_file;
357         struct mm_struct *mm = vma->vm_mm;        329         struct mm_struct *mm = vma->vm_mm;
358         struct kioctx_table *table;               330         struct kioctx_table *table;
359         int i, res = -EINVAL;                     331         int i, res = -EINVAL;
360                                                   332 
361         spin_lock(&mm->ioctx_lock);               333         spin_lock(&mm->ioctx_lock);
362         rcu_read_lock();                          334         rcu_read_lock();
363         table = rcu_dereference(mm->ioctx_tabl    335         table = rcu_dereference(mm->ioctx_table);
364         if (!table)                            << 
365                 goto out_unlock;               << 
366                                                << 
367         for (i = 0; i < table->nr; i++) {         336         for (i = 0; i < table->nr; i++) {
368                 struct kioctx *ctx;               337                 struct kioctx *ctx;
369                                                   338 
370                 ctx = rcu_dereference(table->t    339                 ctx = rcu_dereference(table->table[i]);
371                 if (ctx && ctx->aio_ring_file     340                 if (ctx && ctx->aio_ring_file == file) {
372                         if (!atomic_read(&ctx-    341                         if (!atomic_read(&ctx->dead)) {
373                                 ctx->user_id =    342                                 ctx->user_id = ctx->mmap_base = vma->vm_start;
374                                 res = 0;          343                                 res = 0;
375                         }                         344                         }
376                         break;                    345                         break;
377                 }                                 346                 }
378         }                                         347         }
379                                                   348 
380 out_unlock:                                    << 
381         rcu_read_unlock();                        349         rcu_read_unlock();
382         spin_unlock(&mm->ioctx_lock);             350         spin_unlock(&mm->ioctx_lock);
383         return res;                               351         return res;
384 }                                                 352 }
385                                                   353 
386 static const struct vm_operations_struct aio_r    354 static const struct vm_operations_struct aio_ring_vm_ops = {
387         .mremap         = aio_ring_mremap,        355         .mremap         = aio_ring_mremap,
388 #if IS_ENABLED(CONFIG_MMU)                        356 #if IS_ENABLED(CONFIG_MMU)
389         .fault          = filemap_fault,          357         .fault          = filemap_fault,
390         .map_pages      = filemap_map_pages,      358         .map_pages      = filemap_map_pages,
391         .page_mkwrite   = filemap_page_mkwrite    359         .page_mkwrite   = filemap_page_mkwrite,
392 #endif                                            360 #endif
393 };                                                361 };
394                                                   362 
395 static int aio_ring_mmap(struct file *file, st    363 static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
396 {                                                 364 {
397         vm_flags_set(vma, VM_DONTEXPAND);      !! 365         vma->vm_flags |= VM_DONTEXPAND;
398         vma->vm_ops = &aio_ring_vm_ops;           366         vma->vm_ops = &aio_ring_vm_ops;
399         return 0;                                 367         return 0;
400 }                                                 368 }
401                                                   369 
402 static const struct file_operations aio_ring_f    370 static const struct file_operations aio_ring_fops = {
403         .mmap = aio_ring_mmap,                    371         .mmap = aio_ring_mmap,
404 };                                                372 };
405                                                   373 
406 #if IS_ENABLED(CONFIG_MIGRATION)                  374 #if IS_ENABLED(CONFIG_MIGRATION)
407 static int aio_migrate_folio(struct address_sp !! 375 static int aio_migratepage(struct address_space *mapping, struct page *new,
408                         struct folio *src, enu !! 376                         struct page *old, enum migrate_mode mode)
409 {                                                 377 {
410         struct kioctx *ctx;                       378         struct kioctx *ctx;
411         unsigned long flags;                      379         unsigned long flags;
412         pgoff_t idx;                              380         pgoff_t idx;
413         int rc = 0;                            !! 381         int rc;
                                                   >> 382 
                                                   >> 383         /*
                                                   >> 384          * We cannot support the _NO_COPY case here, because copy needs to
                                                   >> 385          * happen under the ctx->completion_lock. That does not work with the
                                                   >> 386          * migration workflow of MIGRATE_SYNC_NO_COPY.
                                                   >> 387          */
                                                   >> 388         if (mode == MIGRATE_SYNC_NO_COPY)
                                                   >> 389                 return -EINVAL;
414                                                   390 
415         /* mapping->i_private_lock here protec !! 391         rc = 0;
416         spin_lock(&mapping->i_private_lock);   !! 392 
417         ctx = mapping->i_private_data;         !! 393         /* mapping->private_lock here protects against the kioctx teardown.  */
                                                   >> 394         spin_lock(&mapping->private_lock);
                                                   >> 395         ctx = mapping->private_data;
418         if (!ctx) {                               396         if (!ctx) {
419                 rc = -EINVAL;                     397                 rc = -EINVAL;
420                 goto out;                         398                 goto out;
421         }                                         399         }
422                                                   400 
423         /* The ring_lock mutex.  The prevents     401         /* The ring_lock mutex.  The prevents aio_read_events() from writing
424          * to the ring's head, and prevents pa    402          * to the ring's head, and prevents page migration from mucking in
425          * a partially initialized kiotx.         403          * a partially initialized kiotx.
426          */                                       404          */
427         if (!mutex_trylock(&ctx->ring_lock)) {    405         if (!mutex_trylock(&ctx->ring_lock)) {
428                 rc = -EAGAIN;                     406                 rc = -EAGAIN;
429                 goto out;                         407                 goto out;
430         }                                         408         }
431                                                   409 
432         idx = src->index;                      !! 410         idx = old->index;
433         if (idx < (pgoff_t)ctx->nr_pages) {       411         if (idx < (pgoff_t)ctx->nr_pages) {
434                 /* Make sure the old folio has !! 412                 /* Make sure the old page hasn't already been changed */
435                 if (ctx->ring_folios[idx] != s !! 413                 if (ctx->ring_pages[idx] != old)
436                         rc = -EAGAIN;             414                         rc = -EAGAIN;
437         } else                                    415         } else
438                 rc = -EINVAL;                     416                 rc = -EINVAL;
439                                                   417 
440         if (rc != 0)                              418         if (rc != 0)
441                 goto out_unlock;                  419                 goto out_unlock;
442                                                   420 
443         /* Writeback must be complete */          421         /* Writeback must be complete */
444         BUG_ON(folio_test_writeback(src));     !! 422         BUG_ON(PageWriteback(old));
445         folio_get(dst);                        !! 423         get_page(new);
446                                                   424 
447         rc = folio_migrate_mapping(mapping, ds !! 425         rc = migrate_page_move_mapping(mapping, new, old, 1);
448         if (rc != MIGRATEPAGE_SUCCESS) {          426         if (rc != MIGRATEPAGE_SUCCESS) {
449                 folio_put(dst);                !! 427                 put_page(new);
450                 goto out_unlock;                  428                 goto out_unlock;
451         }                                         429         }
452                                                   430 
453         /* Take completion_lock to prevent oth    431         /* Take completion_lock to prevent other writes to the ring buffer
454          * while the old folio is copied to th !! 432          * while the old page is copied to the new.  This prevents new
455          * events from being lost.                433          * events from being lost.
456          */                                       434          */
457         spin_lock_irqsave(&ctx->completion_loc    435         spin_lock_irqsave(&ctx->completion_lock, flags);
458         folio_copy(dst, src);                  !! 436         migrate_page_copy(new, old);
459         folio_migrate_flags(dst, src);         !! 437         BUG_ON(ctx->ring_pages[idx] != old);
460         BUG_ON(ctx->ring_folios[idx] != src);  !! 438         ctx->ring_pages[idx] = new;
461         ctx->ring_folios[idx] = dst;           << 
462         spin_unlock_irqrestore(&ctx->completio    439         spin_unlock_irqrestore(&ctx->completion_lock, flags);
463                                                   440 
464         /* The old folio is no longer accessib !! 441         /* The old page is no longer accessible. */
465         folio_put(src);                        !! 442         put_page(old);
466                                                   443 
467 out_unlock:                                       444 out_unlock:
468         mutex_unlock(&ctx->ring_lock);            445         mutex_unlock(&ctx->ring_lock);
469 out:                                              446 out:
470         spin_unlock(&mapping->i_private_lock); !! 447         spin_unlock(&mapping->private_lock);
471         return rc;                                448         return rc;
472 }                                                 449 }
473 #else                                          << 
474 #define aio_migrate_folio NULL                 << 
475 #endif                                            450 #endif
476                                                   451 
477 static const struct address_space_operations a    452 static const struct address_space_operations aio_ctx_aops = {
478         .dirty_folio    = noop_dirty_folio,    !! 453         .set_page_dirty = __set_page_dirty_no_writeback,
479         .migrate_folio  = aio_migrate_folio,   !! 454 #if IS_ENABLED(CONFIG_MIGRATION)
                                                   >> 455         .migratepage    = aio_migratepage,
                                                   >> 456 #endif
480 };                                                457 };
481                                                   458 
482 static int aio_setup_ring(struct kioctx *ctx,     459 static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
483 {                                                 460 {
484         struct aio_ring *ring;                    461         struct aio_ring *ring;
485         struct mm_struct *mm = current->mm;       462         struct mm_struct *mm = current->mm;
486         unsigned long size, unused;               463         unsigned long size, unused;
487         int nr_pages;                             464         int nr_pages;
488         int i;                                    465         int i;
489         struct file *file;                        466         struct file *file;
490                                                   467 
491         /* Compensate for the ring buffer's he    468         /* Compensate for the ring buffer's head/tail overlap entry */
492         nr_events += 2; /* 1 is required, 2 fo    469         nr_events += 2; /* 1 is required, 2 for good luck */
493                                                   470 
494         size = sizeof(struct aio_ring);           471         size = sizeof(struct aio_ring);
495         size += sizeof(struct io_event) * nr_e    472         size += sizeof(struct io_event) * nr_events;
496                                                   473 
497         nr_pages = PFN_UP(size);                  474         nr_pages = PFN_UP(size);
498         if (nr_pages < 0)                         475         if (nr_pages < 0)
499                 return -EINVAL;                   476                 return -EINVAL;
500                                                   477 
501         file = aio_private_file(ctx, nr_pages)    478         file = aio_private_file(ctx, nr_pages);
502         if (IS_ERR(file)) {                       479         if (IS_ERR(file)) {
503                 ctx->aio_ring_file = NULL;        480                 ctx->aio_ring_file = NULL;
504                 return -ENOMEM;                   481                 return -ENOMEM;
505         }                                         482         }
506                                                   483 
507         ctx->aio_ring_file = file;                484         ctx->aio_ring_file = file;
508         nr_events = (PAGE_SIZE * nr_pages - si    485         nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
509                         / sizeof(struct io_eve    486                         / sizeof(struct io_event);
510                                                   487 
511         ctx->ring_folios = ctx->internal_folio !! 488         ctx->ring_pages = ctx->internal_pages;
512         if (nr_pages > AIO_RING_PAGES) {          489         if (nr_pages > AIO_RING_PAGES) {
513                 ctx->ring_folios = kcalloc(nr_ !! 490                 ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
514                                            GFP !! 491                                           GFP_KERNEL);
515                 if (!ctx->ring_folios) {       !! 492                 if (!ctx->ring_pages) {
516                         put_aio_ring_file(ctx)    493                         put_aio_ring_file(ctx);
517                         return -ENOMEM;           494                         return -ENOMEM;
518                 }                                 495                 }
519         }                                         496         }
520                                                   497 
521         for (i = 0; i < nr_pages; i++) {          498         for (i = 0; i < nr_pages; i++) {
522                 struct folio *folio;           !! 499                 struct page *page;
523                                                !! 500                 page = find_or_create_page(file->f_mapping,
524                 folio = __filemap_get_folio(fi !! 501                                            i, GFP_HIGHUSER | __GFP_ZERO);
525                                             FG !! 502                 if (!page)
526                                             GF << 
527                 if (IS_ERR(folio))             << 
528                         break;                    503                         break;
                                                   >> 504                 pr_debug("pid(%d) page[%d]->count=%d\n",
                                                   >> 505                          current->pid, i, page_count(page));
                                                   >> 506                 SetPageUptodate(page);
                                                   >> 507                 unlock_page(page);
529                                                   508 
530                 pr_debug("pid(%d) [%d] folio-> !! 509                 ctx->ring_pages[i] = page;
531                          folio_ref_count(folio << 
532                 folio_end_read(folio, true);   << 
533                                                << 
534                 ctx->ring_folios[i] = folio;   << 
535         }                                         510         }
536         ctx->nr_pages = i;                        511         ctx->nr_pages = i;
537                                                   512 
538         if (unlikely(i != nr_pages)) {            513         if (unlikely(i != nr_pages)) {
539                 aio_free_ring(ctx);               514                 aio_free_ring(ctx);
540                 return -ENOMEM;                   515                 return -ENOMEM;
541         }                                         516         }
542                                                   517 
543         ctx->mmap_size = nr_pages * PAGE_SIZE;    518         ctx->mmap_size = nr_pages * PAGE_SIZE;
544         pr_debug("attempting mmap of %lu bytes    519         pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
545                                                   520 
546         if (mmap_write_lock_killable(mm)) {       521         if (mmap_write_lock_killable(mm)) {
547                 ctx->mmap_size = 0;               522                 ctx->mmap_size = 0;
548                 aio_free_ring(ctx);               523                 aio_free_ring(ctx);
549                 return -EINTR;                    524                 return -EINTR;
550         }                                         525         }
551                                                   526 
552         ctx->mmap_base = do_mmap(ctx->aio_ring    527         ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
553                                  PROT_READ | P    528                                  PROT_READ | PROT_WRITE,
554                                  MAP_SHARED, 0 !! 529                                  MAP_SHARED, 0, &unused, NULL);
555         mmap_write_unlock(mm);                    530         mmap_write_unlock(mm);
556         if (IS_ERR((void *)ctx->mmap_base)) {     531         if (IS_ERR((void *)ctx->mmap_base)) {
557                 ctx->mmap_size = 0;               532                 ctx->mmap_size = 0;
558                 aio_free_ring(ctx);               533                 aio_free_ring(ctx);
559                 return -ENOMEM;                   534                 return -ENOMEM;
560         }                                         535         }
561                                                   536 
562         pr_debug("mmap address: 0x%08lx\n", ct    537         pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
563                                                   538 
564         ctx->user_id = ctx->mmap_base;            539         ctx->user_id = ctx->mmap_base;
565         ctx->nr_events = nr_events; /* trusted    540         ctx->nr_events = nr_events; /* trusted copy */
566                                                   541 
567         ring = folio_address(ctx->ring_folios[ !! 542         ring = kmap_atomic(ctx->ring_pages[0]);
568         ring->nr = nr_events;   /* user copy *    543         ring->nr = nr_events;   /* user copy */
569         ring->id = ~0U;                           544         ring->id = ~0U;
570         ring->head = ring->tail = 0;              545         ring->head = ring->tail = 0;
571         ring->magic = AIO_RING_MAGIC;             546         ring->magic = AIO_RING_MAGIC;
572         ring->compat_features = AIO_RING_COMPA    547         ring->compat_features = AIO_RING_COMPAT_FEATURES;
573         ring->incompat_features = AIO_RING_INC    548         ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
574         ring->header_length = sizeof(struct ai    549         ring->header_length = sizeof(struct aio_ring);
575         flush_dcache_folio(ctx->ring_folios[0] !! 550         kunmap_atomic(ring);
                                                   >> 551         flush_dcache_page(ctx->ring_pages[0]);
576                                                   552 
577         return 0;                                 553         return 0;
578 }                                                 554 }
579                                                   555 
580 #define AIO_EVENTS_PER_PAGE     (PAGE_SIZE / s    556 #define AIO_EVENTS_PER_PAGE     (PAGE_SIZE / sizeof(struct io_event))
581 #define AIO_EVENTS_FIRST_PAGE   ((PAGE_SIZE -     557 #define AIO_EVENTS_FIRST_PAGE   ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
582 #define AIO_EVENTS_OFFSET       (AIO_EVENTS_PE    558 #define AIO_EVENTS_OFFSET       (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
583                                                   559 
584 void kiocb_set_cancel_fn(struct kiocb *iocb, k    560 void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
585 {                                                 561 {
586         struct aio_kiocb *req;                 !! 562         struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
587         struct kioctx *ctx;                    !! 563         struct kioctx *ctx = req->ki_ctx;
588         unsigned long flags;                      564         unsigned long flags;
589                                                   565 
590         /*                                     << 
591          * kiocb didn't come from aio or is ne << 
592          * ignore it.                          << 
593          */                                    << 
594         if (!(iocb->ki_flags & IOCB_AIO_RW))   << 
595                 return;                        << 
596                                                << 
597         req = container_of(iocb, struct aio_ki << 
598                                                << 
599         if (WARN_ON_ONCE(!list_empty(&req->ki_    566         if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
600                 return;                           567                 return;
601                                                   568 
602         ctx = req->ki_ctx;                     << 
603                                                << 
604         spin_lock_irqsave(&ctx->ctx_lock, flag    569         spin_lock_irqsave(&ctx->ctx_lock, flags);
605         list_add_tail(&req->ki_list, &ctx->act    570         list_add_tail(&req->ki_list, &ctx->active_reqs);
606         req->ki_cancel = cancel;                  571         req->ki_cancel = cancel;
607         spin_unlock_irqrestore(&ctx->ctx_lock,    572         spin_unlock_irqrestore(&ctx->ctx_lock, flags);
608 }                                                 573 }
609 EXPORT_SYMBOL(kiocb_set_cancel_fn);               574 EXPORT_SYMBOL(kiocb_set_cancel_fn);
610                                                   575 
611 /*                                                576 /*
612  * free_ioctx() should be RCU delayed to synch    577  * free_ioctx() should be RCU delayed to synchronize against the RCU
613  * protected lookup_ioctx() and also needs pro    578  * protected lookup_ioctx() and also needs process context to call
614  * aio_free_ring().  Use rcu_work.                579  * aio_free_ring().  Use rcu_work.
615  */                                               580  */
616 static void free_ioctx(struct work_struct *wor    581 static void free_ioctx(struct work_struct *work)
617 {                                                 582 {
618         struct kioctx *ctx = container_of(to_r    583         struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
619                                           free    584                                           free_rwork);
620         pr_debug("freeing %p\n", ctx);            585         pr_debug("freeing %p\n", ctx);
621                                                   586 
622         aio_free_ring(ctx);                       587         aio_free_ring(ctx);
623         free_percpu(ctx->cpu);                    588         free_percpu(ctx->cpu);
624         percpu_ref_exit(&ctx->reqs);              589         percpu_ref_exit(&ctx->reqs);
625         percpu_ref_exit(&ctx->users);             590         percpu_ref_exit(&ctx->users);
626         kmem_cache_free(kioctx_cachep, ctx);      591         kmem_cache_free(kioctx_cachep, ctx);
627 }                                                 592 }
628                                                   593 
629 static void free_ioctx_reqs(struct percpu_ref     594 static void free_ioctx_reqs(struct percpu_ref *ref)
630 {                                                 595 {
631         struct kioctx *ctx = container_of(ref,    596         struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
632                                                   597 
633         /* At this point we know that there ar    598         /* At this point we know that there are no any in-flight requests */
634         if (ctx->rq_wait && atomic_dec_and_tes    599         if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
635                 complete(&ctx->rq_wait->comp);    600                 complete(&ctx->rq_wait->comp);
636                                                   601 
637         /* Synchronize against RCU protected t    602         /* Synchronize against RCU protected table->table[] dereferences */
638         INIT_RCU_WORK(&ctx->free_rwork, free_i    603         INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
639         queue_rcu_work(system_wq, &ctx->free_r    604         queue_rcu_work(system_wq, &ctx->free_rwork);
640 }                                                 605 }
641                                                   606 
642 /*                                                607 /*
643  * When this function runs, the kioctx has bee    608  * When this function runs, the kioctx has been removed from the "hash table"
644  * and ctx->users has dropped to 0, so we know    609  * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
645  * now it's safe to cancel any that need to be    610  * now it's safe to cancel any that need to be.
646  */                                               611  */
647 static void free_ioctx_users(struct percpu_ref    612 static void free_ioctx_users(struct percpu_ref *ref)
648 {                                                 613 {
649         struct kioctx *ctx = container_of(ref,    614         struct kioctx *ctx = container_of(ref, struct kioctx, users);
650         struct aio_kiocb *req;                    615         struct aio_kiocb *req;
651                                                   616 
652         spin_lock_irq(&ctx->ctx_lock);            617         spin_lock_irq(&ctx->ctx_lock);
653                                                   618 
654         while (!list_empty(&ctx->active_reqs))    619         while (!list_empty(&ctx->active_reqs)) {
655                 req = list_first_entry(&ctx->a    620                 req = list_first_entry(&ctx->active_reqs,
656                                        struct     621                                        struct aio_kiocb, ki_list);
657                 req->ki_cancel(&req->rw);         622                 req->ki_cancel(&req->rw);
658                 list_del_init(&req->ki_list);     623                 list_del_init(&req->ki_list);
659         }                                         624         }
660                                                   625 
661         spin_unlock_irq(&ctx->ctx_lock);          626         spin_unlock_irq(&ctx->ctx_lock);
662                                                   627 
663         percpu_ref_kill(&ctx->reqs);              628         percpu_ref_kill(&ctx->reqs);
664         percpu_ref_put(&ctx->reqs);               629         percpu_ref_put(&ctx->reqs);
665 }                                                 630 }
666                                                   631 
667 static int ioctx_add_table(struct kioctx *ctx,    632 static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
668 {                                                 633 {
669         unsigned i, new_nr;                       634         unsigned i, new_nr;
670         struct kioctx_table *table, *old;         635         struct kioctx_table *table, *old;
671         struct aio_ring *ring;                    636         struct aio_ring *ring;
672                                                   637 
673         spin_lock(&mm->ioctx_lock);               638         spin_lock(&mm->ioctx_lock);
674         table = rcu_dereference_raw(mm->ioctx_    639         table = rcu_dereference_raw(mm->ioctx_table);
675                                                   640 
676         while (1) {                               641         while (1) {
677                 if (table)                        642                 if (table)
678                         for (i = 0; i < table-    643                         for (i = 0; i < table->nr; i++)
679                                 if (!rcu_acces    644                                 if (!rcu_access_pointer(table->table[i])) {
680                                         ctx->i    645                                         ctx->id = i;
681                                         rcu_as    646                                         rcu_assign_pointer(table->table[i], ctx);
682                                         spin_u    647                                         spin_unlock(&mm->ioctx_lock);
683                                                   648 
684                                         /* Whi    649                                         /* While kioctx setup is in progress,
685                                          * we     650                                          * we are protected from page migration
686                                          * cha !! 651                                          * changes ring_pages by ->ring_lock.
687                                          */       652                                          */
688                                         ring = !! 653                                         ring = kmap_atomic(ctx->ring_pages[0]);
689                                         ring->    654                                         ring->id = ctx->id;
                                                   >> 655                                         kunmap_atomic(ring);
690                                         return    656                                         return 0;
691                                 }                 657                                 }
692                                                   658 
693                 new_nr = (table ? table->nr :     659                 new_nr = (table ? table->nr : 1) * 4;
694                 spin_unlock(&mm->ioctx_lock);     660                 spin_unlock(&mm->ioctx_lock);
695                                                   661 
696                 table = kzalloc(struct_size(ta !! 662                 table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
                                                   >> 663                                 new_nr, GFP_KERNEL);
697                 if (!table)                       664                 if (!table)
698                         return -ENOMEM;           665                         return -ENOMEM;
699                                                   666 
700                 table->nr = new_nr;               667                 table->nr = new_nr;
701                                                   668 
702                 spin_lock(&mm->ioctx_lock);       669                 spin_lock(&mm->ioctx_lock);
703                 old = rcu_dereference_raw(mm->    670                 old = rcu_dereference_raw(mm->ioctx_table);
704                                                   671 
705                 if (!old) {                       672                 if (!old) {
706                         rcu_assign_pointer(mm-    673                         rcu_assign_pointer(mm->ioctx_table, table);
707                 } else if (table->nr > old->nr    674                 } else if (table->nr > old->nr) {
708                         memcpy(table->table, o    675                         memcpy(table->table, old->table,
709                                old->nr * sizeo    676                                old->nr * sizeof(struct kioctx *));
710                                                   677 
711                         rcu_assign_pointer(mm-    678                         rcu_assign_pointer(mm->ioctx_table, table);
712                         kfree_rcu(old, rcu);      679                         kfree_rcu(old, rcu);
713                 } else {                          680                 } else {
714                         kfree(table);             681                         kfree(table);
715                         table = old;              682                         table = old;
716                 }                                 683                 }
717         }                                         684         }
718 }                                                 685 }
719                                                   686 
720 static void aio_nr_sub(unsigned nr)               687 static void aio_nr_sub(unsigned nr)
721 {                                                 688 {
722         spin_lock(&aio_nr_lock);                  689         spin_lock(&aio_nr_lock);
723         if (WARN_ON(aio_nr - nr > aio_nr))        690         if (WARN_ON(aio_nr - nr > aio_nr))
724                 aio_nr = 0;                       691                 aio_nr = 0;
725         else                                      692         else
726                 aio_nr -= nr;                     693                 aio_nr -= nr;
727         spin_unlock(&aio_nr_lock);                694         spin_unlock(&aio_nr_lock);
728 }                                                 695 }
729                                                   696 
730 /* ioctx_alloc                                    697 /* ioctx_alloc
731  *      Allocates and initializes an ioctx.  R    698  *      Allocates and initializes an ioctx.  Returns an ERR_PTR if it failed.
732  */                                               699  */
733 static struct kioctx *ioctx_alloc(unsigned nr_    700 static struct kioctx *ioctx_alloc(unsigned nr_events)
734 {                                                 701 {
735         struct mm_struct *mm = current->mm;       702         struct mm_struct *mm = current->mm;
736         struct kioctx *ctx;                       703         struct kioctx *ctx;
737         int err = -ENOMEM;                        704         int err = -ENOMEM;
738                                                   705 
739         /*                                        706         /*
740          * Store the original nr_events -- wha    707          * Store the original nr_events -- what userspace passed to io_setup(),
741          * for counting against the global lim    708          * for counting against the global limit -- before it changes.
742          */                                       709          */
743         unsigned int max_reqs = nr_events;        710         unsigned int max_reqs = nr_events;
744                                                   711 
745         /*                                        712         /*
746          * We keep track of the number of avai    713          * We keep track of the number of available ringbuffer slots, to prevent
747          * overflow (reqs_available), and we a    714          * overflow (reqs_available), and we also use percpu counters for this.
748          *                                        715          *
749          * So since up to half the slots might    716          * So since up to half the slots might be on other cpu's percpu counters
750          * and unavailable, double nr_events s    717          * and unavailable, double nr_events so userspace sees what they
751          * expected: additionally, we move req    718          * expected: additionally, we move req_batch slots to/from percpu
752          * counters at a time, so make sure th    719          * counters at a time, so make sure that isn't 0:
753          */                                       720          */
754         nr_events = max(nr_events, num_possibl    721         nr_events = max(nr_events, num_possible_cpus() * 4);
755         nr_events *= 2;                           722         nr_events *= 2;
756                                                   723 
757         /* Prevent overflows */                   724         /* Prevent overflows */
758         if (nr_events > (0x10000000U / sizeof(    725         if (nr_events > (0x10000000U / sizeof(struct io_event))) {
759                 pr_debug("ENOMEM: nr_events to    726                 pr_debug("ENOMEM: nr_events too high\n");
760                 return ERR_PTR(-EINVAL);          727                 return ERR_PTR(-EINVAL);
761         }                                         728         }
762                                                   729 
763         if (!nr_events || (unsigned long)max_r    730         if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
764                 return ERR_PTR(-EAGAIN);          731                 return ERR_PTR(-EAGAIN);
765                                                   732 
766         ctx = kmem_cache_zalloc(kioctx_cachep,    733         ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
767         if (!ctx)                                 734         if (!ctx)
768                 return ERR_PTR(-ENOMEM);          735                 return ERR_PTR(-ENOMEM);
769                                                   736 
770         ctx->max_reqs = max_reqs;                 737         ctx->max_reqs = max_reqs;
771                                                   738 
772         spin_lock_init(&ctx->ctx_lock);           739         spin_lock_init(&ctx->ctx_lock);
773         spin_lock_init(&ctx->completion_lock);    740         spin_lock_init(&ctx->completion_lock);
774         mutex_init(&ctx->ring_lock);              741         mutex_init(&ctx->ring_lock);
775         /* Protect against page migration thro    742         /* Protect against page migration throughout kiotx setup by keeping
776          * the ring_lock mutex held until setu    743          * the ring_lock mutex held until setup is complete. */
777         mutex_lock(&ctx->ring_lock);              744         mutex_lock(&ctx->ring_lock);
778         init_waitqueue_head(&ctx->wait);          745         init_waitqueue_head(&ctx->wait);
779                                                   746 
780         INIT_LIST_HEAD(&ctx->active_reqs);        747         INIT_LIST_HEAD(&ctx->active_reqs);
781                                                   748 
782         if (percpu_ref_init(&ctx->users, free_    749         if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
783                 goto err;                         750                 goto err;
784                                                   751 
785         if (percpu_ref_init(&ctx->reqs, free_i    752         if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
786                 goto err;                         753                 goto err;
787                                                   754 
788         ctx->cpu = alloc_percpu(struct kioctx_    755         ctx->cpu = alloc_percpu(struct kioctx_cpu);
789         if (!ctx->cpu)                            756         if (!ctx->cpu)
790                 goto err;                         757                 goto err;
791                                                   758 
792         err = aio_setup_ring(ctx, nr_events);     759         err = aio_setup_ring(ctx, nr_events);
793         if (err < 0)                              760         if (err < 0)
794                 goto err;                         761                 goto err;
795                                                   762 
796         atomic_set(&ctx->reqs_available, ctx->    763         atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
797         ctx->req_batch = (ctx->nr_events - 1)     764         ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
798         if (ctx->req_batch < 1)                   765         if (ctx->req_batch < 1)
799                 ctx->req_batch = 1;               766                 ctx->req_batch = 1;
800                                                   767 
801         /* limit the number of system wide aio    768         /* limit the number of system wide aios */
802         spin_lock(&aio_nr_lock);                  769         spin_lock(&aio_nr_lock);
803         if (aio_nr + ctx->max_reqs > aio_max_n    770         if (aio_nr + ctx->max_reqs > aio_max_nr ||
804             aio_nr + ctx->max_reqs < aio_nr) {    771             aio_nr + ctx->max_reqs < aio_nr) {
805                 spin_unlock(&aio_nr_lock);        772                 spin_unlock(&aio_nr_lock);
806                 err = -EAGAIN;                    773                 err = -EAGAIN;
807                 goto err_ctx;                     774                 goto err_ctx;
808         }                                         775         }
809         aio_nr += ctx->max_reqs;                  776         aio_nr += ctx->max_reqs;
810         spin_unlock(&aio_nr_lock);                777         spin_unlock(&aio_nr_lock);
811                                                   778 
812         percpu_ref_get(&ctx->users);    /* io_    779         percpu_ref_get(&ctx->users);    /* io_setup() will drop this ref */
813         percpu_ref_get(&ctx->reqs);     /* fre    780         percpu_ref_get(&ctx->reqs);     /* free_ioctx_users() will drop this */
814                                                   781 
815         err = ioctx_add_table(ctx, mm);           782         err = ioctx_add_table(ctx, mm);
816         if (err)                                  783         if (err)
817                 goto err_cleanup;                 784                 goto err_cleanup;
818                                                   785 
819         /* Release the ring_lock mutex now tha    786         /* Release the ring_lock mutex now that all setup is complete. */
820         mutex_unlock(&ctx->ring_lock);            787         mutex_unlock(&ctx->ring_lock);
821                                                   788 
822         pr_debug("allocated ioctx %p[%ld]: mm=    789         pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
823                  ctx, ctx->user_id, mm, ctx->n    790                  ctx, ctx->user_id, mm, ctx->nr_events);
824         return ctx;                               791         return ctx;
825                                                   792 
826 err_cleanup:                                      793 err_cleanup:
827         aio_nr_sub(ctx->max_reqs);                794         aio_nr_sub(ctx->max_reqs);
828 err_ctx:                                          795 err_ctx:
829         atomic_set(&ctx->dead, 1);                796         atomic_set(&ctx->dead, 1);
830         if (ctx->mmap_size)                       797         if (ctx->mmap_size)
831                 vm_munmap(ctx->mmap_base, ctx-    798                 vm_munmap(ctx->mmap_base, ctx->mmap_size);
832         aio_free_ring(ctx);                       799         aio_free_ring(ctx);
833 err:                                              800 err:
834         mutex_unlock(&ctx->ring_lock);            801         mutex_unlock(&ctx->ring_lock);
835         free_percpu(ctx->cpu);                    802         free_percpu(ctx->cpu);
836         percpu_ref_exit(&ctx->reqs);              803         percpu_ref_exit(&ctx->reqs);
837         percpu_ref_exit(&ctx->users);             804         percpu_ref_exit(&ctx->users);
838         kmem_cache_free(kioctx_cachep, ctx);      805         kmem_cache_free(kioctx_cachep, ctx);
839         pr_debug("error allocating ioctx %d\n"    806         pr_debug("error allocating ioctx %d\n", err);
840         return ERR_PTR(err);                      807         return ERR_PTR(err);
841 }                                                 808 }
842                                                   809 
843 /* kill_ioctx                                     810 /* kill_ioctx
844  *      Cancels all outstanding aio requests o    811  *      Cancels all outstanding aio requests on an aio context.  Used
845  *      when the processes owning a context ha    812  *      when the processes owning a context have all exited to encourage
846  *      the rapid destruction of the kioctx.      813  *      the rapid destruction of the kioctx.
847  */                                               814  */
848 static int kill_ioctx(struct mm_struct *mm, st    815 static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
849                       struct ctx_rq_wait *wait    816                       struct ctx_rq_wait *wait)
850 {                                                 817 {
851         struct kioctx_table *table;               818         struct kioctx_table *table;
852                                                   819 
853         spin_lock(&mm->ioctx_lock);               820         spin_lock(&mm->ioctx_lock);
854         if (atomic_xchg(&ctx->dead, 1)) {         821         if (atomic_xchg(&ctx->dead, 1)) {
855                 spin_unlock(&mm->ioctx_lock);     822                 spin_unlock(&mm->ioctx_lock);
856                 return -EINVAL;                   823                 return -EINVAL;
857         }                                         824         }
858                                                   825 
859         table = rcu_dereference_raw(mm->ioctx_    826         table = rcu_dereference_raw(mm->ioctx_table);
860         WARN_ON(ctx != rcu_access_pointer(tabl    827         WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
861         RCU_INIT_POINTER(table->table[ctx->id]    828         RCU_INIT_POINTER(table->table[ctx->id], NULL);
862         spin_unlock(&mm->ioctx_lock);             829         spin_unlock(&mm->ioctx_lock);
863                                                   830 
864         /* free_ioctx_reqs() will do the neces    831         /* free_ioctx_reqs() will do the necessary RCU synchronization */
865         wake_up_all(&ctx->wait);                  832         wake_up_all(&ctx->wait);
866                                                   833 
867         /*                                        834         /*
868          * It'd be more correct to do this in     835          * It'd be more correct to do this in free_ioctx(), after all
869          * the outstanding kiocbs have finishe    836          * the outstanding kiocbs have finished - but by then io_destroy
870          * has already returned, so io_setup()    837          * has already returned, so io_setup() could potentially return
871          * -EAGAIN with no ioctxs actually in     838          * -EAGAIN with no ioctxs actually in use (as far as userspace
872          *  could tell).                          839          *  could tell).
873          */                                       840          */
874         aio_nr_sub(ctx->max_reqs);                841         aio_nr_sub(ctx->max_reqs);
875                                                   842 
876         if (ctx->mmap_size)                       843         if (ctx->mmap_size)
877                 vm_munmap(ctx->mmap_base, ctx-    844                 vm_munmap(ctx->mmap_base, ctx->mmap_size);
878                                                   845 
879         ctx->rq_wait = wait;                      846         ctx->rq_wait = wait;
880         percpu_ref_kill(&ctx->users);             847         percpu_ref_kill(&ctx->users);
881         return 0;                                 848         return 0;
882 }                                                 849 }
883                                                   850 
884 /*                                                851 /*
885  * exit_aio: called when the last user of mm g    852  * exit_aio: called when the last user of mm goes away.  At this point, there is
886  * no way for any new requests to be submited     853  * no way for any new requests to be submited or any of the io_* syscalls to be
887  * called on the context.                         854  * called on the context.
888  *                                                855  *
889  * There may be outstanding kiocbs, but free_i    856  * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
890  * them.                                          857  * them.
891  */                                               858  */
892 void exit_aio(struct mm_struct *mm)               859 void exit_aio(struct mm_struct *mm)
893 {                                                 860 {
894         struct kioctx_table *table = rcu_deref    861         struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
895         struct ctx_rq_wait wait;                  862         struct ctx_rq_wait wait;
896         int i, skipped;                           863         int i, skipped;
897                                                   864 
898         if (!table)                               865         if (!table)
899                 return;                           866                 return;
900                                                   867 
901         atomic_set(&wait.count, table->nr);       868         atomic_set(&wait.count, table->nr);
902         init_completion(&wait.comp);              869         init_completion(&wait.comp);
903                                                   870 
904         skipped = 0;                              871         skipped = 0;
905         for (i = 0; i < table->nr; ++i) {         872         for (i = 0; i < table->nr; ++i) {
906                 struct kioctx *ctx =              873                 struct kioctx *ctx =
907                         rcu_dereference_protec    874                         rcu_dereference_protected(table->table[i], true);
908                                                   875 
909                 if (!ctx) {                       876                 if (!ctx) {
910                         skipped++;                877                         skipped++;
911                         continue;                 878                         continue;
912                 }                                 879                 }
913                                                   880 
914                 /*                                881                 /*
915                  * We don't need to bother wit    882                  * We don't need to bother with munmap() here - exit_mmap(mm)
916                  * is coming and it'll unmap e    883                  * is coming and it'll unmap everything. And we simply can't,
917                  * this is not necessarily our    884                  * this is not necessarily our ->mm.
918                  * Since kill_ioctx() uses non    885                  * Since kill_ioctx() uses non-zero ->mmap_size as indicator
919                  * that it needs to unmap the     886                  * that it needs to unmap the area, just set it to 0.
920                  */                               887                  */
921                 ctx->mmap_size = 0;               888                 ctx->mmap_size = 0;
922                 kill_ioctx(mm, ctx, &wait);       889                 kill_ioctx(mm, ctx, &wait);
923         }                                         890         }
924                                                   891 
925         if (!atomic_sub_and_test(skipped, &wai    892         if (!atomic_sub_and_test(skipped, &wait.count)) {
926                 /* Wait until all IO for the c    893                 /* Wait until all IO for the context are done. */
927                 wait_for_completion(&wait.comp    894                 wait_for_completion(&wait.comp);
928         }                                         895         }
929                                                   896 
930         RCU_INIT_POINTER(mm->ioctx_table, NULL    897         RCU_INIT_POINTER(mm->ioctx_table, NULL);
931         kfree(table);                             898         kfree(table);
932 }                                                 899 }
933                                                   900 
934 static void put_reqs_available(struct kioctx *    901 static void put_reqs_available(struct kioctx *ctx, unsigned nr)
935 {                                                 902 {
936         struct kioctx_cpu *kcpu;                  903         struct kioctx_cpu *kcpu;
937         unsigned long flags;                      904         unsigned long flags;
938                                                   905 
939         local_irq_save(flags);                    906         local_irq_save(flags);
940         kcpu = this_cpu_ptr(ctx->cpu);            907         kcpu = this_cpu_ptr(ctx->cpu);
941         kcpu->reqs_available += nr;               908         kcpu->reqs_available += nr;
942                                                   909 
943         while (kcpu->reqs_available >= ctx->re    910         while (kcpu->reqs_available >= ctx->req_batch * 2) {
944                 kcpu->reqs_available -= ctx->r    911                 kcpu->reqs_available -= ctx->req_batch;
945                 atomic_add(ctx->req_batch, &ct    912                 atomic_add(ctx->req_batch, &ctx->reqs_available);
946         }                                         913         }
947                                                   914 
948         local_irq_restore(flags);                 915         local_irq_restore(flags);
949 }                                                 916 }
950                                                   917 
951 static bool __get_reqs_available(struct kioctx    918 static bool __get_reqs_available(struct kioctx *ctx)
952 {                                                 919 {
953         struct kioctx_cpu *kcpu;                  920         struct kioctx_cpu *kcpu;
954         bool ret = false;                         921         bool ret = false;
955         unsigned long flags;                      922         unsigned long flags;
956                                                   923 
957         local_irq_save(flags);                    924         local_irq_save(flags);
958         kcpu = this_cpu_ptr(ctx->cpu);            925         kcpu = this_cpu_ptr(ctx->cpu);
959         if (!kcpu->reqs_available) {              926         if (!kcpu->reqs_available) {
960                 int avail = atomic_read(&ctx-> !! 927                 int old, avail = atomic_read(&ctx->reqs_available);
961                                                   928 
962                 do {                              929                 do {
963                         if (avail < ctx->req_b    930                         if (avail < ctx->req_batch)
964                                 goto out;         931                                 goto out;
965                 } while (!atomic_try_cmpxchg(& !! 932 
966                                              & !! 933                         old = avail;
                                                   >> 934                         avail = atomic_cmpxchg(&ctx->reqs_available,
                                                   >> 935                                                avail, avail - ctx->req_batch);
                                                   >> 936                 } while (avail != old);
967                                                   937 
968                 kcpu->reqs_available += ctx->r    938                 kcpu->reqs_available += ctx->req_batch;
969         }                                         939         }
970                                                   940 
971         ret = true;                               941         ret = true;
972         kcpu->reqs_available--;                   942         kcpu->reqs_available--;
973 out:                                              943 out:
974         local_irq_restore(flags);                 944         local_irq_restore(flags);
975         return ret;                               945         return ret;
976 }                                                 946 }
977                                                   947 
978 /* refill_reqs_available                          948 /* refill_reqs_available
979  *      Updates the reqs_available reference c    949  *      Updates the reqs_available reference counts used for tracking the
980  *      number of free slots in the completion    950  *      number of free slots in the completion ring.  This can be called
981  *      from aio_complete() (to optimistically    951  *      from aio_complete() (to optimistically update reqs_available) or
982  *      from aio_get_req() (the we're out of e    952  *      from aio_get_req() (the we're out of events case).  It must be
983  *      called holding ctx->completion_lock.      953  *      called holding ctx->completion_lock.
984  */                                               954  */
985 static void refill_reqs_available(struct kioct    955 static void refill_reqs_available(struct kioctx *ctx, unsigned head,
986                                   unsigned tai    956                                   unsigned tail)
987 {                                                 957 {
988         unsigned events_in_ring, completed;       958         unsigned events_in_ring, completed;
989                                                   959 
990         /* Clamp head since userland can write    960         /* Clamp head since userland can write to it. */
991         head %= ctx->nr_events;                   961         head %= ctx->nr_events;
992         if (head <= tail)                         962         if (head <= tail)
993                 events_in_ring = tail - head;     963                 events_in_ring = tail - head;
994         else                                      964         else
995                 events_in_ring = ctx->nr_event    965                 events_in_ring = ctx->nr_events - (head - tail);
996                                                   966 
997         completed = ctx->completed_events;        967         completed = ctx->completed_events;
998         if (events_in_ring < completed)           968         if (events_in_ring < completed)
999                 completed -= events_in_ring;      969                 completed -= events_in_ring;
1000         else                                     970         else
1001                 completed = 0;                   971                 completed = 0;
1002                                                  972 
1003         if (!completed)                          973         if (!completed)
1004                 return;                          974                 return;
1005                                                  975 
1006         ctx->completed_events -= completed;      976         ctx->completed_events -= completed;
1007         put_reqs_available(ctx, completed);      977         put_reqs_available(ctx, completed);
1008 }                                                978 }
1009                                                  979 
1010 /* user_refill_reqs_available                    980 /* user_refill_reqs_available
1011  *      Called to refill reqs_available when     981  *      Called to refill reqs_available when aio_get_req() encounters an
1012  *      out of space in the completion ring.     982  *      out of space in the completion ring.
1013  */                                              983  */
1014 static void user_refill_reqs_available(struct    984 static void user_refill_reqs_available(struct kioctx *ctx)
1015 {                                                985 {
1016         spin_lock_irq(&ctx->completion_lock);    986         spin_lock_irq(&ctx->completion_lock);
1017         if (ctx->completed_events) {             987         if (ctx->completed_events) {
1018                 struct aio_ring *ring;           988                 struct aio_ring *ring;
1019                 unsigned head;                   989                 unsigned head;
1020                                                  990 
1021                 /* Access of ring->head may r    991                 /* Access of ring->head may race with aio_read_events_ring()
1022                  * here, but that's okay sinc    992                  * here, but that's okay since whether we read the old version
1023                  * or the new version, and ei    993                  * or the new version, and either will be valid.  The important
1024                  * part is that head cannot p    994                  * part is that head cannot pass tail since we prevent
1025                  * aio_complete() from updati    995                  * aio_complete() from updating tail by holding
1026                  * ctx->completion_lock.  Eve    996                  * ctx->completion_lock.  Even if head is invalid, the check
1027                  * against ctx->completed_eve    997                  * against ctx->completed_events below will make sure we do the
1028                  * safe/right thing.             998                  * safe/right thing.
1029                  */                              999                  */
1030                 ring = folio_address(ctx->rin !! 1000                 ring = kmap_atomic(ctx->ring_pages[0]);
1031                 head = ring->head;               1001                 head = ring->head;
                                                   >> 1002                 kunmap_atomic(ring);
1032                                                  1003 
1033                 refill_reqs_available(ctx, he    1004                 refill_reqs_available(ctx, head, ctx->tail);
1034         }                                        1005         }
1035                                                  1006 
1036         spin_unlock_irq(&ctx->completion_lock    1007         spin_unlock_irq(&ctx->completion_lock);
1037 }                                                1008 }
1038                                                  1009 
1039 static bool get_reqs_available(struct kioctx     1010 static bool get_reqs_available(struct kioctx *ctx)
1040 {                                                1011 {
1041         if (__get_reqs_available(ctx))           1012         if (__get_reqs_available(ctx))
1042                 return true;                     1013                 return true;
1043         user_refill_reqs_available(ctx);         1014         user_refill_reqs_available(ctx);
1044         return __get_reqs_available(ctx);        1015         return __get_reqs_available(ctx);
1045 }                                                1016 }
1046                                                  1017 
1047 /* aio_get_req                                   1018 /* aio_get_req
1048  *      Allocate a slot for an aio request.      1019  *      Allocate a slot for an aio request.
1049  * Returns NULL if no requests are free.         1020  * Returns NULL if no requests are free.
1050  *                                               1021  *
1051  * The refcount is initialized to 2 - one for    1022  * The refcount is initialized to 2 - one for the async op completion,
1052  * one for the synchronous code that does thi    1023  * one for the synchronous code that does this.
1053  */                                              1024  */
1054 static inline struct aio_kiocb *aio_get_req(s    1025 static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
1055 {                                                1026 {
1056         struct aio_kiocb *req;                   1027         struct aio_kiocb *req;
1057                                                  1028 
1058         req = kmem_cache_alloc(kiocb_cachep,     1029         req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
1059         if (unlikely(!req))                      1030         if (unlikely(!req))
1060                 return NULL;                     1031                 return NULL;
1061                                                  1032 
1062         if (unlikely(!get_reqs_available(ctx)    1033         if (unlikely(!get_reqs_available(ctx))) {
1063                 kmem_cache_free(kiocb_cachep,    1034                 kmem_cache_free(kiocb_cachep, req);
1064                 return NULL;                     1035                 return NULL;
1065         }                                        1036         }
1066                                                  1037 
1067         percpu_ref_get(&ctx->reqs);              1038         percpu_ref_get(&ctx->reqs);
1068         req->ki_ctx = ctx;                       1039         req->ki_ctx = ctx;
1069         INIT_LIST_HEAD(&req->ki_list);           1040         INIT_LIST_HEAD(&req->ki_list);
1070         refcount_set(&req->ki_refcnt, 2);        1041         refcount_set(&req->ki_refcnt, 2);
1071         req->ki_eventfd = NULL;                  1042         req->ki_eventfd = NULL;
1072         return req;                              1043         return req;
1073 }                                                1044 }
1074                                                  1045 
1075 static struct kioctx *lookup_ioctx(unsigned l    1046 static struct kioctx *lookup_ioctx(unsigned long ctx_id)
1076 {                                                1047 {
1077         struct aio_ring __user *ring  = (void    1048         struct aio_ring __user *ring  = (void __user *)ctx_id;
1078         struct mm_struct *mm = current->mm;      1049         struct mm_struct *mm = current->mm;
1079         struct kioctx *ctx, *ret = NULL;         1050         struct kioctx *ctx, *ret = NULL;
1080         struct kioctx_table *table;              1051         struct kioctx_table *table;
1081         unsigned id;                             1052         unsigned id;
1082                                                  1053 
1083         if (get_user(id, &ring->id))             1054         if (get_user(id, &ring->id))
1084                 return NULL;                     1055                 return NULL;
1085                                                  1056 
1086         rcu_read_lock();                         1057         rcu_read_lock();
1087         table = rcu_dereference(mm->ioctx_tab    1058         table = rcu_dereference(mm->ioctx_table);
1088                                                  1059 
1089         if (!table || id >= table->nr)           1060         if (!table || id >= table->nr)
1090                 goto out;                        1061                 goto out;
1091                                                  1062 
1092         id = array_index_nospec(id, table->nr    1063         id = array_index_nospec(id, table->nr);
1093         ctx = rcu_dereference(table->table[id    1064         ctx = rcu_dereference(table->table[id]);
1094         if (ctx && ctx->user_id == ctx_id) {     1065         if (ctx && ctx->user_id == ctx_id) {
1095                 if (percpu_ref_tryget_live(&c    1066                 if (percpu_ref_tryget_live(&ctx->users))
1096                         ret = ctx;               1067                         ret = ctx;
1097         }                                        1068         }
1098 out:                                             1069 out:
1099         rcu_read_unlock();                       1070         rcu_read_unlock();
1100         return ret;                              1071         return ret;
1101 }                                                1072 }
1102                                                  1073 
1103 static inline void iocb_destroy(struct aio_ki    1074 static inline void iocb_destroy(struct aio_kiocb *iocb)
1104 {                                                1075 {
1105         if (iocb->ki_eventfd)                    1076         if (iocb->ki_eventfd)
1106                 eventfd_ctx_put(iocb->ki_even    1077                 eventfd_ctx_put(iocb->ki_eventfd);
1107         if (iocb->ki_filp)                       1078         if (iocb->ki_filp)
1108                 fput(iocb->ki_filp);             1079                 fput(iocb->ki_filp);
1109         percpu_ref_put(&iocb->ki_ctx->reqs);     1080         percpu_ref_put(&iocb->ki_ctx->reqs);
1110         kmem_cache_free(kiocb_cachep, iocb);     1081         kmem_cache_free(kiocb_cachep, iocb);
1111 }                                                1082 }
1112                                                  1083 
1113 struct aio_waiter {                           << 
1114         struct wait_queue_entry w;            << 
1115         size_t                  min_nr;       << 
1116 };                                            << 
1117                                               << 
1118 /* aio_complete                                  1084 /* aio_complete
1119  *      Called when the io request on the giv    1085  *      Called when the io request on the given iocb is complete.
1120  */                                              1086  */
1121 static void aio_complete(struct aio_kiocb *io    1087 static void aio_complete(struct aio_kiocb *iocb)
1122 {                                                1088 {
1123         struct kioctx   *ctx = iocb->ki_ctx;     1089         struct kioctx   *ctx = iocb->ki_ctx;
1124         struct aio_ring *ring;                   1090         struct aio_ring *ring;
1125         struct io_event *ev_page, *event;        1091         struct io_event *ev_page, *event;
1126         unsigned tail, pos, head, avail;      !! 1092         unsigned tail, pos, head;
1127         unsigned long   flags;                   1093         unsigned long   flags;
1128                                                  1094 
1129         /*                                       1095         /*
1130          * Add a completion event to the ring    1096          * Add a completion event to the ring buffer. Must be done holding
1131          * ctx->completion_lock to prevent ot    1097          * ctx->completion_lock to prevent other code from messing with the tail
1132          * pointer since we might be called f    1098          * pointer since we might be called from irq context.
1133          */                                      1099          */
1134         spin_lock_irqsave(&ctx->completion_lo    1100         spin_lock_irqsave(&ctx->completion_lock, flags);
1135                                                  1101 
1136         tail = ctx->tail;                        1102         tail = ctx->tail;
1137         pos = tail + AIO_EVENTS_OFFSET;          1103         pos = tail + AIO_EVENTS_OFFSET;
1138                                                  1104 
1139         if (++tail >= ctx->nr_events)            1105         if (++tail >= ctx->nr_events)
1140                 tail = 0;                        1106                 tail = 0;
1141                                                  1107 
1142         ev_page = folio_address(ctx->ring_fol !! 1108         ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1143         event = ev_page + pos % AIO_EVENTS_PE    1109         event = ev_page + pos % AIO_EVENTS_PER_PAGE;
1144                                                  1110 
1145         *event = iocb->ki_res;                   1111         *event = iocb->ki_res;
1146                                                  1112 
1147         flush_dcache_folio(ctx->ring_folios[p !! 1113         kunmap_atomic(ev_page);
                                                   >> 1114         flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1148                                                  1115 
1149         pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\    1116         pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
1150                  (void __user *)(unsigned lon    1117                  (void __user *)(unsigned long)iocb->ki_res.obj,
1151                  iocb->ki_res.data, iocb->ki_    1118                  iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);
1152                                                  1119 
1153         /* after flagging the request as done    1120         /* after flagging the request as done, we
1154          * must never even look at it again      1121          * must never even look at it again
1155          */                                      1122          */
1156         smp_wmb();      /* make event visible    1123         smp_wmb();      /* make event visible before updating tail */
1157                                                  1124 
1158         ctx->tail = tail;                        1125         ctx->tail = tail;
1159                                                  1126 
1160         ring = folio_address(ctx->ring_folios !! 1127         ring = kmap_atomic(ctx->ring_pages[0]);
1161         head = ring->head;                       1128         head = ring->head;
1162         ring->tail = tail;                       1129         ring->tail = tail;
1163         flush_dcache_folio(ctx->ring_folios[0 !! 1130         kunmap_atomic(ring);
                                                   >> 1131         flush_dcache_page(ctx->ring_pages[0]);
1164                                                  1132 
1165         ctx->completed_events++;                 1133         ctx->completed_events++;
1166         if (ctx->completed_events > 1)           1134         if (ctx->completed_events > 1)
1167                 refill_reqs_available(ctx, he    1135                 refill_reqs_available(ctx, head, tail);
1168                                               << 
1169         avail = tail > head                   << 
1170                 ? tail - head                 << 
1171                 : tail + ctx->nr_events - hea << 
1172         spin_unlock_irqrestore(&ctx->completi    1136         spin_unlock_irqrestore(&ctx->completion_lock, flags);
1173                                                  1137 
1174         pr_debug("added to ring %p at [%u]\n"    1138         pr_debug("added to ring %p at [%u]\n", iocb, tail);
1175                                                  1139 
1176         /*                                       1140         /*
1177          * Check if the user asked us to deli    1141          * Check if the user asked us to deliver the result through an
1178          * eventfd. The eventfd_signal() func    1142          * eventfd. The eventfd_signal() function is safe to be called
1179          * from IRQ context.                     1143          * from IRQ context.
1180          */                                      1144          */
1181         if (iocb->ki_eventfd)                    1145         if (iocb->ki_eventfd)
1182                 eventfd_signal(iocb->ki_event !! 1146                 eventfd_signal(iocb->ki_eventfd, 1);
1183                                                  1147 
1184         /*                                       1148         /*
1185          * We have to order our ring_info tai    1149          * We have to order our ring_info tail store above and test
1186          * of the wait list below outside the    1150          * of the wait list below outside the wait lock.  This is
1187          * like in wake_up_bit() where cleari    1151          * like in wake_up_bit() where clearing a bit has to be
1188          * ordered with the unlocked test.       1152          * ordered with the unlocked test.
1189          */                                      1153          */
1190         smp_mb();                                1154         smp_mb();
1191                                                  1155 
1192         if (waitqueue_active(&ctx->wait)) {   !! 1156         if (waitqueue_active(&ctx->wait))
1193                 struct aio_waiter *curr, *nex !! 1157                 wake_up(&ctx->wait);
1194                 unsigned long flags;          << 
1195                                               << 
1196                 spin_lock_irqsave(&ctx->wait. << 
1197                 list_for_each_entry_safe(curr << 
1198                         if (avail >= curr->mi << 
1199                                 wake_up_proce << 
1200                                 list_del_init << 
1201                         }                     << 
1202                 spin_unlock_irqrestore(&ctx-> << 
1203         }                                     << 
1204 }                                                1158 }
1205                                                  1159 
1206 static inline void iocb_put(struct aio_kiocb     1160 static inline void iocb_put(struct aio_kiocb *iocb)
1207 {                                                1161 {
1208         if (refcount_dec_and_test(&iocb->ki_r    1162         if (refcount_dec_and_test(&iocb->ki_refcnt)) {
1209                 aio_complete(iocb);              1163                 aio_complete(iocb);
1210                 iocb_destroy(iocb);              1164                 iocb_destroy(iocb);
1211         }                                        1165         }
1212 }                                                1166 }
1213                                                  1167 
1214 /* aio_read_events_ring                          1168 /* aio_read_events_ring
1215  *      Pull an event off of the ioctx's even    1169  *      Pull an event off of the ioctx's event ring.  Returns the number of
1216  *      events fetched                           1170  *      events fetched
1217  */                                              1171  */
1218 static long aio_read_events_ring(struct kioct    1172 static long aio_read_events_ring(struct kioctx *ctx,
1219                                  struct io_ev    1173                                  struct io_event __user *event, long nr)
1220 {                                                1174 {
1221         struct aio_ring *ring;                   1175         struct aio_ring *ring;
1222         unsigned head, tail, pos;                1176         unsigned head, tail, pos;
1223         long ret = 0;                            1177         long ret = 0;
1224         int copy_ret;                            1178         int copy_ret;
1225                                                  1179 
1226         /*                                       1180         /*
1227          * The mutex can block and wake us up    1181          * The mutex can block and wake us up and that will cause
1228          * wait_event_interruptible_hrtimeout    1182          * wait_event_interruptible_hrtimeout() to schedule without sleeping
1229          * and repeat. This should be rare en    1183          * and repeat. This should be rare enough that it doesn't cause
1230          * peformance issues. See the comment    1184          * peformance issues. See the comment in read_events() for more detail.
1231          */                                      1185          */
1232         sched_annotate_sleep();                  1186         sched_annotate_sleep();
1233         mutex_lock(&ctx->ring_lock);             1187         mutex_lock(&ctx->ring_lock);
1234                                                  1188 
1235         /* Access to ->ring_folios here is pr !! 1189         /* Access to ->ring_pages here is protected by ctx->ring_lock. */
1236         ring = folio_address(ctx->ring_folios !! 1190         ring = kmap_atomic(ctx->ring_pages[0]);
1237         head = ring->head;                       1191         head = ring->head;
1238         tail = ring->tail;                       1192         tail = ring->tail;
                                                   >> 1193         kunmap_atomic(ring);
1239                                                  1194 
1240         /*                                       1195         /*
1241          * Ensure that once we've read the cu    1196          * Ensure that once we've read the current tail pointer, that
1242          * we also see the events that were s    1197          * we also see the events that were stored up to the tail.
1243          */                                      1198          */
1244         smp_rmb();                               1199         smp_rmb();
1245                                                  1200 
1246         pr_debug("h%u t%u m%u\n", head, tail,    1201         pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
1247                                                  1202 
1248         if (head == tail)                        1203         if (head == tail)
1249                 goto out;                        1204                 goto out;
1250                                                  1205 
1251         head %= ctx->nr_events;                  1206         head %= ctx->nr_events;
1252         tail %= ctx->nr_events;                  1207         tail %= ctx->nr_events;
1253                                                  1208 
1254         while (ret < nr) {                       1209         while (ret < nr) {
1255                 long avail;                      1210                 long avail;
1256                 struct io_event *ev;             1211                 struct io_event *ev;
1257                 struct folio *folio;          !! 1212                 struct page *page;
1258                                                  1213 
1259                 avail = (head <= tail ?  tail    1214                 avail = (head <= tail ?  tail : ctx->nr_events) - head;
1260                 if (head == tail)                1215                 if (head == tail)
1261                         break;                   1216                         break;
1262                                                  1217 
1263                 pos = head + AIO_EVENTS_OFFSE    1218                 pos = head + AIO_EVENTS_OFFSET;
1264                 folio = ctx->ring_folios[pos  !! 1219                 page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
1265                 pos %= AIO_EVENTS_PER_PAGE;      1220                 pos %= AIO_EVENTS_PER_PAGE;
1266                                                  1221 
1267                 avail = min(avail, nr - ret);    1222                 avail = min(avail, nr - ret);
1268                 avail = min_t(long, avail, AI    1223                 avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
1269                                                  1224 
1270                 ev = folio_address(folio);    !! 1225                 ev = kmap(page);
1271                 copy_ret = copy_to_user(event    1226                 copy_ret = copy_to_user(event + ret, ev + pos,
1272                                         sizeo    1227                                         sizeof(*ev) * avail);
                                                   >> 1228                 kunmap(page);
1273                                                  1229 
1274                 if (unlikely(copy_ret)) {        1230                 if (unlikely(copy_ret)) {
1275                         ret = -EFAULT;           1231                         ret = -EFAULT;
1276                         goto out;                1232                         goto out;
1277                 }                                1233                 }
1278                                                  1234 
1279                 ret += avail;                    1235                 ret += avail;
1280                 head += avail;                   1236                 head += avail;
1281                 head %= ctx->nr_events;          1237                 head %= ctx->nr_events;
1282         }                                        1238         }
1283                                                  1239 
1284         ring = folio_address(ctx->ring_folios !! 1240         ring = kmap_atomic(ctx->ring_pages[0]);
1285         ring->head = head;                       1241         ring->head = head;
1286         flush_dcache_folio(ctx->ring_folios[0 !! 1242         kunmap_atomic(ring);
                                                   >> 1243         flush_dcache_page(ctx->ring_pages[0]);
1287                                                  1244 
1288         pr_debug("%li  h%u t%u\n", ret, head,    1245         pr_debug("%li  h%u t%u\n", ret, head, tail);
1289 out:                                             1246 out:
1290         mutex_unlock(&ctx->ring_lock);           1247         mutex_unlock(&ctx->ring_lock);
1291                                                  1248 
1292         return ret;                              1249         return ret;
1293 }                                                1250 }
1294                                                  1251 
1295 static bool aio_read_events(struct kioctx *ct    1252 static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
1296                             struct io_event _    1253                             struct io_event __user *event, long *i)
1297 {                                                1254 {
1298         long ret = aio_read_events_ring(ctx,     1255         long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
1299                                                  1256 
1300         if (ret > 0)                             1257         if (ret > 0)
1301                 *i += ret;                       1258                 *i += ret;
1302                                                  1259 
1303         if (unlikely(atomic_read(&ctx->dead))    1260         if (unlikely(atomic_read(&ctx->dead)))
1304                 ret = -EINVAL;                   1261                 ret = -EINVAL;
1305                                                  1262 
1306         if (!*i)                                 1263         if (!*i)
1307                 *i = ret;                        1264                 *i = ret;
1308                                                  1265 
1309         return ret < 0 || *i >= min_nr;          1266         return ret < 0 || *i >= min_nr;
1310 }                                                1267 }
1311                                                  1268 
1312 static long read_events(struct kioctx *ctx, l    1269 static long read_events(struct kioctx *ctx, long min_nr, long nr,
1313                         struct io_event __use    1270                         struct io_event __user *event,
1314                         ktime_t until)           1271                         ktime_t until)
1315 {                                                1272 {
1316         struct hrtimer_sleeper  t;            !! 1273         long ret = 0;
1317         struct aio_waiter       w;            << 
1318         long ret = 0, ret2 = 0;               << 
1319                                                  1274 
1320         /*                                       1275         /*
1321          * Note that aio_read_events() is bei    1276          * Note that aio_read_events() is being called as the conditional - i.e.
1322          * we're calling it after prepare_to_    1277          * we're calling it after prepare_to_wait() has set task state to
1323          * TASK_INTERRUPTIBLE.                   1278          * TASK_INTERRUPTIBLE.
1324          *                                       1279          *
1325          * But aio_read_events() can block, a    1280          * But aio_read_events() can block, and if it blocks it's going to flip
1326          * the task state back to TASK_RUNNIN    1281          * the task state back to TASK_RUNNING.
1327          *                                       1282          *
1328          * This should be ok, provided it doe    1283          * This should be ok, provided it doesn't flip the state back to
1329          * TASK_RUNNING and return 0 too much    1284          * TASK_RUNNING and return 0 too much - that causes us to spin. That
1330          * will only happen if the mutex_lock    1285          * will only happen if the mutex_lock() call blocks, and we then find
1331          * the ringbuffer empty. So in practi    1286          * the ringbuffer empty. So in practice we should be ok, but it's
1332          * something to be aware of when touc    1287          * something to be aware of when touching this code.
1333          */                                      1288          */
1334         aio_read_events(ctx, min_nr, nr, even !! 1289         if (until == 0)
1335         if (until == 0 || ret < 0 || ret >= m !! 1290                 aio_read_events(ctx, min_nr, nr, event, &ret);
1336                 return ret;                   !! 1291         else
1337                                               !! 1292                 wait_event_interruptible_hrtimeout(ctx->wait,
1338         hrtimer_init_sleeper_on_stack(&t, CLO !! 1293                                 aio_read_events(ctx, min_nr, nr, event, &ret),
1339         if (until != KTIME_MAX) {             !! 1294                                 until);
1340                 hrtimer_set_expires_range_ns( << 
1341                 hrtimer_sleeper_start_expires << 
1342         }                                     << 
1343                                               << 
1344         init_wait(&w.w);                      << 
1345                                               << 
1346         while (1) {                           << 
1347                 unsigned long nr_got = ret;   << 
1348                                               << 
1349                 w.min_nr = min_nr - ret;      << 
1350                                               << 
1351                 ret2 = prepare_to_wait_event( << 
1352                 if (!ret2 && !t.task)         << 
1353                         ret2 = -ETIME;        << 
1354                                               << 
1355                 if (aio_read_events(ctx, min_ << 
1356                         break;                << 
1357                                               << 
1358                 if (nr_got == ret)            << 
1359                         schedule();           << 
1360         }                                     << 
1361                                               << 
1362         finish_wait(&ctx->wait, &w.w);        << 
1363         hrtimer_cancel(&t.timer);             << 
1364         destroy_hrtimer_on_stack(&t.timer);   << 
1365                                               << 
1366         return ret;                              1295         return ret;
1367 }                                                1296 }
1368                                                  1297 
1369 /* sys_io_setup:                                 1298 /* sys_io_setup:
1370  *      Create an aio_context capable of rece    1299  *      Create an aio_context capable of receiving at least nr_events.
1371  *      ctxp must not point to an aio_context    1300  *      ctxp must not point to an aio_context that already exists, and
1372  *      must be initialized to 0 prior to the    1301  *      must be initialized to 0 prior to the call.  On successful
1373  *      creation of the aio_context, *ctxp is    1302  *      creation of the aio_context, *ctxp is filled in with the resulting 
1374  *      handle.  May fail with -EINVAL if *ct    1303  *      handle.  May fail with -EINVAL if *ctxp is not initialized,
1375  *      if the specified nr_events exceeds in    1304  *      if the specified nr_events exceeds internal limits.  May fail 
1376  *      with -EAGAIN if the specified nr_even    1305  *      with -EAGAIN if the specified nr_events exceeds the user's limit 
1377  *      of available events.  May fail with -    1306  *      of available events.  May fail with -ENOMEM if insufficient kernel
1378  *      resources are available.  May fail wi    1307  *      resources are available.  May fail with -EFAULT if an invalid
1379  *      pointer is passed for ctxp.  Will fai    1308  *      pointer is passed for ctxp.  Will fail with -ENOSYS if not
1380  *      implemented.                             1309  *      implemented.
1381  */                                              1310  */
1382 SYSCALL_DEFINE2(io_setup, unsigned, nr_events    1311 SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
1383 {                                                1312 {
1384         struct kioctx *ioctx = NULL;             1313         struct kioctx *ioctx = NULL;
1385         unsigned long ctx;                       1314         unsigned long ctx;
1386         long ret;                                1315         long ret;
1387                                                  1316 
1388         ret = get_user(ctx, ctxp);               1317         ret = get_user(ctx, ctxp);
1389         if (unlikely(ret))                       1318         if (unlikely(ret))
1390                 goto out;                        1319                 goto out;
1391                                                  1320 
1392         ret = -EINVAL;                           1321         ret = -EINVAL;
1393         if (unlikely(ctx || nr_events == 0))     1322         if (unlikely(ctx || nr_events == 0)) {
1394                 pr_debug("EINVAL: ctx %lu nr_    1323                 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1395                          ctx, nr_events);        1324                          ctx, nr_events);
1396                 goto out;                        1325                 goto out;
1397         }                                        1326         }
1398                                                  1327 
1399         ioctx = ioctx_alloc(nr_events);          1328         ioctx = ioctx_alloc(nr_events);
1400         ret = PTR_ERR(ioctx);                    1329         ret = PTR_ERR(ioctx);
1401         if (!IS_ERR(ioctx)) {                    1330         if (!IS_ERR(ioctx)) {
1402                 ret = put_user(ioctx->user_id    1331                 ret = put_user(ioctx->user_id, ctxp);
1403                 if (ret)                         1332                 if (ret)
1404                         kill_ioctx(current->m    1333                         kill_ioctx(current->mm, ioctx, NULL);
1405                 percpu_ref_put(&ioctx->users)    1334                 percpu_ref_put(&ioctx->users);
1406         }                                        1335         }
1407                                                  1336 
1408 out:                                             1337 out:
1409         return ret;                              1338         return ret;
1410 }                                                1339 }
1411                                                  1340 
1412 #ifdef CONFIG_COMPAT                             1341 #ifdef CONFIG_COMPAT
1413 COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr    1342 COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
1414 {                                                1343 {
1415         struct kioctx *ioctx = NULL;             1344         struct kioctx *ioctx = NULL;
1416         unsigned long ctx;                       1345         unsigned long ctx;
1417         long ret;                                1346         long ret;
1418                                                  1347 
1419         ret = get_user(ctx, ctx32p);             1348         ret = get_user(ctx, ctx32p);
1420         if (unlikely(ret))                       1349         if (unlikely(ret))
1421                 goto out;                        1350                 goto out;
1422                                                  1351 
1423         ret = -EINVAL;                           1352         ret = -EINVAL;
1424         if (unlikely(ctx || nr_events == 0))     1353         if (unlikely(ctx || nr_events == 0)) {
1425                 pr_debug("EINVAL: ctx %lu nr_    1354                 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1426                          ctx, nr_events);        1355                          ctx, nr_events);
1427                 goto out;                        1356                 goto out;
1428         }                                        1357         }
1429                                                  1358 
1430         ioctx = ioctx_alloc(nr_events);          1359         ioctx = ioctx_alloc(nr_events);
1431         ret = PTR_ERR(ioctx);                    1360         ret = PTR_ERR(ioctx);
1432         if (!IS_ERR(ioctx)) {                    1361         if (!IS_ERR(ioctx)) {
1433                 /* truncating is ok because i    1362                 /* truncating is ok because it's a user address */
1434                 ret = put_user((u32)ioctx->us    1363                 ret = put_user((u32)ioctx->user_id, ctx32p);
1435                 if (ret)                         1364                 if (ret)
1436                         kill_ioctx(current->m    1365                         kill_ioctx(current->mm, ioctx, NULL);
1437                 percpu_ref_put(&ioctx->users)    1366                 percpu_ref_put(&ioctx->users);
1438         }                                        1367         }
1439                                                  1368 
1440 out:                                             1369 out:
1441         return ret;                              1370         return ret;
1442 }                                                1371 }
1443 #endif                                           1372 #endif
1444                                                  1373 
1445 /* sys_io_destroy:                               1374 /* sys_io_destroy:
1446  *      Destroy the aio_context specified.  M    1375  *      Destroy the aio_context specified.  May cancel any outstanding 
1447  *      AIOs and block on completion.  Will f    1376  *      AIOs and block on completion.  Will fail with -ENOSYS if not
1448  *      implemented.  May fail with -EINVAL i    1377  *      implemented.  May fail with -EINVAL if the context pointed to
1449  *      is invalid.                              1378  *      is invalid.
1450  */                                              1379  */
1451 SYSCALL_DEFINE1(io_destroy, aio_context_t, ct    1380 SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
1452 {                                                1381 {
1453         struct kioctx *ioctx = lookup_ioctx(c    1382         struct kioctx *ioctx = lookup_ioctx(ctx);
1454         if (likely(NULL != ioctx)) {             1383         if (likely(NULL != ioctx)) {
1455                 struct ctx_rq_wait wait;         1384                 struct ctx_rq_wait wait;
1456                 int ret;                         1385                 int ret;
1457                                                  1386 
1458                 init_completion(&wait.comp);     1387                 init_completion(&wait.comp);
1459                 atomic_set(&wait.count, 1);      1388                 atomic_set(&wait.count, 1);
1460                                                  1389 
1461                 /* Pass requests_done to kill    1390                 /* Pass requests_done to kill_ioctx() where it can be set
1462                  * in a thread-safe way. If w    1391                  * in a thread-safe way. If we try to set it here then we have
1463                  * a race condition if two io    1392                  * a race condition if two io_destroy() called simultaneously.
1464                  */                              1393                  */
1465                 ret = kill_ioctx(current->mm,    1394                 ret = kill_ioctx(current->mm, ioctx, &wait);
1466                 percpu_ref_put(&ioctx->users)    1395                 percpu_ref_put(&ioctx->users);
1467                                                  1396 
1468                 /* Wait until all IO for the     1397                 /* Wait until all IO for the context are done. Otherwise kernel
1469                  * keep using user-space buff    1398                  * keep using user-space buffers even if user thinks the context
1470                  * is destroyed.                 1399                  * is destroyed.
1471                  */                              1400                  */
1472                 if (!ret)                        1401                 if (!ret)
1473                         wait_for_completion(&    1402                         wait_for_completion(&wait.comp);
1474                                                  1403 
1475                 return ret;                      1404                 return ret;
1476         }                                        1405         }
1477         pr_debug("EINVAL: invalid context id\    1406         pr_debug("EINVAL: invalid context id\n");
1478         return -EINVAL;                          1407         return -EINVAL;
1479 }                                                1408 }
1480                                                  1409 
1481 static void aio_remove_iocb(struct aio_kiocb     1410 static void aio_remove_iocb(struct aio_kiocb *iocb)
1482 {                                                1411 {
1483         struct kioctx *ctx = iocb->ki_ctx;       1412         struct kioctx *ctx = iocb->ki_ctx;
1484         unsigned long flags;                     1413         unsigned long flags;
1485                                                  1414 
1486         spin_lock_irqsave(&ctx->ctx_lock, fla    1415         spin_lock_irqsave(&ctx->ctx_lock, flags);
1487         list_del(&iocb->ki_list);                1416         list_del(&iocb->ki_list);
1488         spin_unlock_irqrestore(&ctx->ctx_lock    1417         spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1489 }                                                1418 }
1490                                                  1419 
1491 static void aio_complete_rw(struct kiocb *kio !! 1420 static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
1492 {                                                1421 {
1493         struct aio_kiocb *iocb = container_of    1422         struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
1494                                                  1423 
1495         if (!list_empty_careful(&iocb->ki_lis    1424         if (!list_empty_careful(&iocb->ki_list))
1496                 aio_remove_iocb(iocb);           1425                 aio_remove_iocb(iocb);
1497                                                  1426 
1498         if (kiocb->ki_flags & IOCB_WRITE) {      1427         if (kiocb->ki_flags & IOCB_WRITE) {
1499                 struct inode *inode = file_in    1428                 struct inode *inode = file_inode(kiocb->ki_filp);
1500                                                  1429 
                                                   >> 1430                 /*
                                                   >> 1431                  * Tell lockdep we inherited freeze protection from submission
                                                   >> 1432                  * thread.
                                                   >> 1433                  */
1501                 if (S_ISREG(inode->i_mode))      1434                 if (S_ISREG(inode->i_mode))
1502                         kiocb_end_write(kiocb !! 1435                         __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
                                                   >> 1436                 file_end_write(kiocb->ki_filp);
1503         }                                        1437         }
1504                                                  1438 
1505         iocb->ki_res.res = res;                  1439         iocb->ki_res.res = res;
1506         iocb->ki_res.res2 = 0;                !! 1440         iocb->ki_res.res2 = res2;
1507         iocb_put(iocb);                          1441         iocb_put(iocb);
1508 }                                                1442 }
1509                                                  1443 
1510 static int aio_prep_rw(struct kiocb *req, con !! 1444 static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
1511 {                                                1445 {
1512         int ret;                                 1446         int ret;
1513                                                  1447 
1514         req->ki_complete = aio_complete_rw;      1448         req->ki_complete = aio_complete_rw;
1515         req->private = NULL;                     1449         req->private = NULL;
1516         req->ki_pos = iocb->aio_offset;          1450         req->ki_pos = iocb->aio_offset;
1517         req->ki_flags = req->ki_filp->f_iocb_ !! 1451         req->ki_flags = iocb_flags(req->ki_filp);
1518         if (iocb->aio_flags & IOCB_FLAG_RESFD    1452         if (iocb->aio_flags & IOCB_FLAG_RESFD)
1519                 req->ki_flags |= IOCB_EVENTFD    1453                 req->ki_flags |= IOCB_EVENTFD;
                                                   >> 1454         req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp));
1520         if (iocb->aio_flags & IOCB_FLAG_IOPRI    1455         if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
1521                 /*                               1456                 /*
1522                  * If the IOCB_FLAG_IOPRIO fl    1457                  * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
1523                  * aio_reqprio is interpreted    1458                  * aio_reqprio is interpreted as an I/O scheduling
1524                  * class and priority.           1459                  * class and priority.
1525                  */                              1460                  */
1526                 ret = ioprio_check_cap(iocb->    1461                 ret = ioprio_check_cap(iocb->aio_reqprio);
1527                 if (ret) {                       1462                 if (ret) {
1528                         pr_debug("aio ioprio     1463                         pr_debug("aio ioprio check cap error: %d\n", ret);
1529                         return ret;              1464                         return ret;
1530                 }                                1465                 }
1531                                                  1466 
1532                 req->ki_ioprio = iocb->aio_re    1467                 req->ki_ioprio = iocb->aio_reqprio;
1533         } else                                   1468         } else
1534                 req->ki_ioprio = get_current_    1469                 req->ki_ioprio = get_current_ioprio();
1535                                                  1470 
1536         ret = kiocb_set_rw_flags(req, iocb->a !! 1471         ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
1537         if (unlikely(ret))                       1472         if (unlikely(ret))
1538                 return ret;                      1473                 return ret;
1539                                                  1474 
1540         req->ki_flags &= ~IOCB_HIPRI; /* no o    1475         req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
1541         return 0;                                1476         return 0;
1542 }                                                1477 }
1543                                                  1478 
1544 static ssize_t aio_setup_rw(int rw, const str    1479 static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
1545                 struct iovec **iovec, bool ve    1480                 struct iovec **iovec, bool vectored, bool compat,
1546                 struct iov_iter *iter)           1481                 struct iov_iter *iter)
1547 {                                                1482 {
1548         void __user *buf = (void __user *)(ui    1483         void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
1549         size_t len = iocb->aio_nbytes;           1484         size_t len = iocb->aio_nbytes;
1550                                                  1485 
1551         if (!vectored) {                         1486         if (!vectored) {
1552                 ssize_t ret = import_ubuf(rw, !! 1487                 ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
1553                 *iovec = NULL;                   1488                 *iovec = NULL;
1554                 return ret;                      1489                 return ret;
1555         }                                        1490         }
1556                                                  1491 
1557         return __import_iovec(rw, buf, len, U    1492         return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);
1558 }                                                1493 }
1559                                                  1494 
1560 static inline void aio_rw_done(struct kiocb *    1495 static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
1561 {                                                1496 {
1562         switch (ret) {                           1497         switch (ret) {
1563         case -EIOCBQUEUED:                       1498         case -EIOCBQUEUED:
1564                 break;                           1499                 break;
1565         case -ERESTARTSYS:                       1500         case -ERESTARTSYS:
1566         case -ERESTARTNOINTR:                    1501         case -ERESTARTNOINTR:
1567         case -ERESTARTNOHAND:                    1502         case -ERESTARTNOHAND:
1568         case -ERESTART_RESTARTBLOCK:             1503         case -ERESTART_RESTARTBLOCK:
1569                 /*                               1504                 /*
1570                  * There's no easy way to res    1505                  * There's no easy way to restart the syscall since other AIO's
1571                  * may be already running. Ju    1506                  * may be already running. Just fail this IO with EINTR.
1572                  */                              1507                  */
1573                 ret = -EINTR;                    1508                 ret = -EINTR;
1574                 fallthrough;                     1509                 fallthrough;
1575         default:                                 1510         default:
1576                 req->ki_complete(req, ret);   !! 1511                 req->ki_complete(req, ret, 0);
1577         }                                        1512         }
1578 }                                                1513 }
1579                                                  1514 
1580 static int aio_read(struct kiocb *req, const     1515 static int aio_read(struct kiocb *req, const struct iocb *iocb,
1581                         bool vectored, bool c    1516                         bool vectored, bool compat)
1582 {                                                1517 {
1583         struct iovec inline_vecs[UIO_FASTIOV]    1518         struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1584         struct iov_iter iter;                    1519         struct iov_iter iter;
1585         struct file *file;                       1520         struct file *file;
1586         int ret;                                 1521         int ret;
1587                                                  1522 
1588         ret = aio_prep_rw(req, iocb, READ);   !! 1523         ret = aio_prep_rw(req, iocb);
1589         if (ret)                                 1524         if (ret)
1590                 return ret;                      1525                 return ret;
1591         file = req->ki_filp;                     1526         file = req->ki_filp;
1592         if (unlikely(!(file->f_mode & FMODE_R    1527         if (unlikely(!(file->f_mode & FMODE_READ)))
1593                 return -EBADF;                   1528                 return -EBADF;
                                                   >> 1529         ret = -EINVAL;
1594         if (unlikely(!file->f_op->read_iter))    1530         if (unlikely(!file->f_op->read_iter))
1595                 return -EINVAL;                  1531                 return -EINVAL;
1596                                                  1532 
1597         ret = aio_setup_rw(ITER_DEST, iocb, & !! 1533         ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
1598         if (ret < 0)                             1534         if (ret < 0)
1599                 return ret;                      1535                 return ret;
1600         ret = rw_verify_area(READ, file, &req    1536         ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
1601         if (!ret)                                1537         if (!ret)
1602                 aio_rw_done(req, file->f_op-> !! 1538                 aio_rw_done(req, call_read_iter(file, req, &iter));
1603         kfree(iovec);                            1539         kfree(iovec);
1604         return ret;                              1540         return ret;
1605 }                                                1541 }
1606                                                  1542 
1607 static int aio_write(struct kiocb *req, const    1543 static int aio_write(struct kiocb *req, const struct iocb *iocb,
1608                          bool vectored, bool     1544                          bool vectored, bool compat)
1609 {                                                1545 {
1610         struct iovec inline_vecs[UIO_FASTIOV]    1546         struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1611         struct iov_iter iter;                    1547         struct iov_iter iter;
1612         struct file *file;                       1548         struct file *file;
1613         int ret;                                 1549         int ret;
1614                                                  1550 
1615         ret = aio_prep_rw(req, iocb, WRITE);  !! 1551         ret = aio_prep_rw(req, iocb);
1616         if (ret)                                 1552         if (ret)
1617                 return ret;                      1553                 return ret;
1618         file = req->ki_filp;                     1554         file = req->ki_filp;
1619                                                  1555 
1620         if (unlikely(!(file->f_mode & FMODE_W    1556         if (unlikely(!(file->f_mode & FMODE_WRITE)))
1621                 return -EBADF;                   1557                 return -EBADF;
1622         if (unlikely(!file->f_op->write_iter)    1558         if (unlikely(!file->f_op->write_iter))
1623                 return -EINVAL;                  1559                 return -EINVAL;
1624                                                  1560 
1625         ret = aio_setup_rw(ITER_SOURCE, iocb, !! 1561         ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
1626         if (ret < 0)                             1562         if (ret < 0)
1627                 return ret;                      1563                 return ret;
1628         ret = rw_verify_area(WRITE, file, &re    1564         ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
1629         if (!ret) {                              1565         if (!ret) {
1630                 if (S_ISREG(file_inode(file)- !! 1566                 /*
1631                         kiocb_start_write(req !! 1567                  * Open-code file_start_write here to grab freeze protection,
                                                   >> 1568                  * which will be released by another thread in
                                                   >> 1569                  * aio_complete_rw().  Fool lockdep by telling it the lock got
                                                   >> 1570                  * released so that it doesn't complain about the held lock when
                                                   >> 1571                  * we return to userspace.
                                                   >> 1572                  */
                                                   >> 1573                 if (S_ISREG(file_inode(file)->i_mode)) {
                                                   >> 1574                         sb_start_write(file_inode(file)->i_sb);
                                                   >> 1575                         __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
                                                   >> 1576                 }
1632                 req->ki_flags |= IOCB_WRITE;     1577                 req->ki_flags |= IOCB_WRITE;
1633                 aio_rw_done(req, file->f_op-> !! 1578                 aio_rw_done(req, call_write_iter(file, req, &iter));
1634         }                                        1579         }
1635         kfree(iovec);                            1580         kfree(iovec);
1636         return ret;                              1581         return ret;
1637 }                                                1582 }
1638                                                  1583 
1639 static void aio_fsync_work(struct work_struct    1584 static void aio_fsync_work(struct work_struct *work)
1640 {                                                1585 {
1641         struct aio_kiocb *iocb = container_of    1586         struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);
1642         const struct cred *old_cred = overrid    1587         const struct cred *old_cred = override_creds(iocb->fsync.creds);
1643                                                  1588 
1644         iocb->ki_res.res = vfs_fsync(iocb->fs    1589         iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
1645         revert_creds(old_cred);                  1590         revert_creds(old_cred);
1646         put_cred(iocb->fsync.creds);             1591         put_cred(iocb->fsync.creds);
1647         iocb_put(iocb);                          1592         iocb_put(iocb);
1648 }                                                1593 }
1649                                                  1594 
1650 static int aio_fsync(struct fsync_iocb *req,     1595 static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
1651                      bool datasync)              1596                      bool datasync)
1652 {                                                1597 {
1653         if (unlikely(iocb->aio_buf || iocb->a    1598         if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
1654                         iocb->aio_rw_flags))     1599                         iocb->aio_rw_flags))
1655                 return -EINVAL;                  1600                 return -EINVAL;
1656                                                  1601 
1657         if (unlikely(!req->file->f_op->fsync)    1602         if (unlikely(!req->file->f_op->fsync))
1658                 return -EINVAL;                  1603                 return -EINVAL;
1659                                                  1604 
1660         req->creds = prepare_creds();            1605         req->creds = prepare_creds();
1661         if (!req->creds)                         1606         if (!req->creds)
1662                 return -ENOMEM;                  1607                 return -ENOMEM;
1663                                                  1608 
1664         req->datasync = datasync;                1609         req->datasync = datasync;
1665         INIT_WORK(&req->work, aio_fsync_work)    1610         INIT_WORK(&req->work, aio_fsync_work);
1666         schedule_work(&req->work);               1611         schedule_work(&req->work);
1667         return 0;                                1612         return 0;
1668 }                                                1613 }
1669                                                  1614 
1670 static void aio_poll_put_work(struct work_str    1615 static void aio_poll_put_work(struct work_struct *work)
1671 {                                                1616 {
1672         struct poll_iocb *req = container_of(    1617         struct poll_iocb *req = container_of(work, struct poll_iocb, work);
1673         struct aio_kiocb *iocb = container_of    1618         struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1674                                                  1619 
1675         iocb_put(iocb);                          1620         iocb_put(iocb);
1676 }                                                1621 }
1677                                                  1622 
1678 /*                                            << 
1679  * Safely lock the waitqueue which the reques << 
1680  * case where the ->poll() provider decides t << 
1681  *                                            << 
1682  * Returns true on success, meaning that req- << 
1683  * is on req->head, and an RCU read lock was  << 
1684  * request was already removed from its waitq << 
1685  */                                           << 
1686 static bool poll_iocb_lock_wq(struct poll_ioc << 
1687 {                                             << 
1688         wait_queue_head_t *head;              << 
1689                                               << 
1690         /*                                    << 
1691          * While we hold the waitqueue lock a << 
1692          * wake_up_pollfree() will wait for u << 
1693          * lock in the first place can race w << 
1694          *                                    << 
1695          * We solve this as eventpoll does: b << 
1696          * all users of wake_up_pollfree() wi << 
1697          * we enter rcu_read_lock() and see t << 
1698          * non-NULL, we can then lock it with << 
1699          * under us, then check whether the r << 
1700          *                                    << 
1701          * Keep holding rcu_read_lock() as lo << 
1702          * case the caller deletes the entry  << 
1703          * In that case, only RCU prevents th << 
1704          */                                   << 
1705         rcu_read_lock();                      << 
1706         head = smp_load_acquire(&req->head);  << 
1707         if (head) {                           << 
1708                 spin_lock(&head->lock);       << 
1709                 if (!list_empty(&req->wait.en << 
1710                         return true;          << 
1711                 spin_unlock(&head->lock);     << 
1712         }                                     << 
1713         rcu_read_unlock();                    << 
1714         return false;                         << 
1715 }                                             << 
1716                                               << 
1717 static void poll_iocb_unlock_wq(struct poll_i << 
1718 {                                             << 
1719         spin_unlock(&req->head->lock);        << 
1720         rcu_read_unlock();                    << 
1721 }                                             << 
1722                                               << 
1723 static void aio_poll_complete_work(struct wor    1623 static void aio_poll_complete_work(struct work_struct *work)
1724 {                                                1624 {
1725         struct poll_iocb *req = container_of(    1625         struct poll_iocb *req = container_of(work, struct poll_iocb, work);
1726         struct aio_kiocb *iocb = container_of    1626         struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1727         struct poll_table_struct pt = { ._key    1627         struct poll_table_struct pt = { ._key = req->events };
1728         struct kioctx *ctx = iocb->ki_ctx;       1628         struct kioctx *ctx = iocb->ki_ctx;
1729         __poll_t mask = 0;                       1629         __poll_t mask = 0;
1730                                                  1630 
1731         if (!READ_ONCE(req->cancelled))          1631         if (!READ_ONCE(req->cancelled))
1732                 mask = vfs_poll(req->file, &p    1632                 mask = vfs_poll(req->file, &pt) & req->events;
1733                                                  1633 
1734         /*                                       1634         /*
1735          * Note that ->ki_cancel callers also    1635          * Note that ->ki_cancel callers also delete iocb from active_reqs after
1736          * calling ->ki_cancel.  We need the     1636          * calling ->ki_cancel.  We need the ctx_lock roundtrip here to
1737          * synchronize with them.  In the can    1637          * synchronize with them.  In the cancellation case the list_del_init
1738          * itself is not actually needed, but    1638          * itself is not actually needed, but harmless so we keep it in to
1739          * avoid further branches in the fast    1639          * avoid further branches in the fast path.
1740          */                                      1640          */
1741         spin_lock_irq(&ctx->ctx_lock);           1641         spin_lock_irq(&ctx->ctx_lock);
1742         if (poll_iocb_lock_wq(req)) {         !! 1642         if (!mask && !READ_ONCE(req->cancelled)) {
1743                 if (!mask && !READ_ONCE(req-> !! 1643                 add_wait_queue(req->head, &req->wait);
1744                         /*                    !! 1644                 spin_unlock_irq(&ctx->ctx_lock);
1745                          * The request isn't  !! 1645                 return;
1746                          * Reschedule complet !! 1646         }
1747                          */                   << 
1748                         if (req->work_need_re << 
1749                                 schedule_work << 
1750                                 req->work_nee << 
1751                         } else {              << 
1752                                 req->work_sch << 
1753                         }                     << 
1754                         poll_iocb_unlock_wq(r << 
1755                         spin_unlock_irq(&ctx- << 
1756                         return;               << 
1757                 }                             << 
1758                 list_del_init(&req->wait.entr << 
1759                 poll_iocb_unlock_wq(req);     << 
1760         } /* else, POLLFREE has freed the wai << 
1761         list_del_init(&iocb->ki_list);           1647         list_del_init(&iocb->ki_list);
1762         iocb->ki_res.res = mangle_poll(mask);    1648         iocb->ki_res.res = mangle_poll(mask);
                                                   >> 1649         req->done = true;
1763         spin_unlock_irq(&ctx->ctx_lock);         1650         spin_unlock_irq(&ctx->ctx_lock);
1764                                                  1651 
1765         iocb_put(iocb);                          1652         iocb_put(iocb);
1766 }                                                1653 }
1767                                                  1654 
1768 /* assumes we are called with irqs disabled *    1655 /* assumes we are called with irqs disabled */
1769 static int aio_poll_cancel(struct kiocb *iocb    1656 static int aio_poll_cancel(struct kiocb *iocb)
1770 {                                                1657 {
1771         struct aio_kiocb *aiocb = container_o    1658         struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
1772         struct poll_iocb *req = &aiocb->poll;    1659         struct poll_iocb *req = &aiocb->poll;
1773                                                  1660 
1774         if (poll_iocb_lock_wq(req)) {         !! 1661         spin_lock(&req->head->lock);
1775                 WRITE_ONCE(req->cancelled, tr !! 1662         WRITE_ONCE(req->cancelled, true);
1776                 if (!req->work_scheduled) {   !! 1663         if (!list_empty(&req->wait.entry)) {
1777                         schedule_work(&aiocb- !! 1664                 list_del_init(&req->wait.entry);
1778                         req->work_scheduled = !! 1665                 schedule_work(&aiocb->poll.work);
1779                 }                             !! 1666         }
1780                 poll_iocb_unlock_wq(req);     !! 1667         spin_unlock(&req->head->lock);
1781         } /* else, the request was force-canc << 
1782                                                  1668 
1783         return 0;                                1669         return 0;
1784 }                                                1670 }
1785                                                  1671 
1786 static int aio_poll_wake(struct wait_queue_en    1672 static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
1787                 void *key)                       1673                 void *key)
1788 {                                                1674 {
1789         struct poll_iocb *req = container_of(    1675         struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
1790         struct aio_kiocb *iocb = container_of    1676         struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1791         __poll_t mask = key_to_poll(key);        1677         __poll_t mask = key_to_poll(key);
1792         unsigned long flags;                     1678         unsigned long flags;
1793                                                  1679 
1794         /* for instances that support it chec    1680         /* for instances that support it check for an event match first: */
1795         if (mask && !(mask & req->events))       1681         if (mask && !(mask & req->events))
1796                 return 0;                        1682                 return 0;
1797                                                  1683 
1798         /*                                    !! 1684         list_del_init(&req->wait.entry);
1799          * Complete the request inline if pos !! 1685 
1800          * conditions be met:                 !! 1686         if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
1801          *   1. An event mask must have been  << 
1802          *      instead, then mask == 0 and w << 
1803          *      the events, so inline complet << 
1804          *   2. The completion work must not  << 
1805          *   3. ctx_lock must not be busy.  W << 
1806          *      already hold the waitqueue lo << 
1807          *      locking order.  Use irqsave/i << 
1808          *      filesystems (e.g. fuse) call  << 
1809          *      yet IRQs have to be disabled  << 
1810          */                                   << 
1811         if (mask && !req->work_scheduled &&   << 
1812             spin_trylock_irqsave(&iocb->ki_ct << 
1813                 struct kioctx *ctx = iocb->ki    1687                 struct kioctx *ctx = iocb->ki_ctx;
1814                                                  1688 
1815                 list_del_init(&req->wait.entr !! 1689                 /*
                                                   >> 1690                  * Try to complete the iocb inline if we can. Use
                                                   >> 1691                  * irqsave/irqrestore because not all filesystems (e.g. fuse)
                                                   >> 1692                  * call this function with IRQs disabled and because IRQs
                                                   >> 1693                  * have to be disabled before ctx_lock is obtained.
                                                   >> 1694                  */
1816                 list_del(&iocb->ki_list);        1695                 list_del(&iocb->ki_list);
1817                 iocb->ki_res.res = mangle_pol    1696                 iocb->ki_res.res = mangle_poll(mask);
1818                 if (iocb->ki_eventfd && !even !! 1697                 req->done = true;
                                                   >> 1698                 if (iocb->ki_eventfd && eventfd_signal_count()) {
1819                         iocb = NULL;             1699                         iocb = NULL;
1820                         INIT_WORK(&req->work,    1700                         INIT_WORK(&req->work, aio_poll_put_work);
1821                         schedule_work(&req->w    1701                         schedule_work(&req->work);
1822                 }                                1702                 }
1823                 spin_unlock_irqrestore(&ctx->    1703                 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1824                 if (iocb)                        1704                 if (iocb)
1825                         iocb_put(iocb);          1705                         iocb_put(iocb);
1826         } else {                                 1706         } else {
1827                 /*                            !! 1707                 schedule_work(&req->work);
1828                  * Schedule the completion wo << 
1829                  * scheduled, record that ano << 
1830                  *                            << 
1831                  * Don't remove the request f << 
1832                  * not actually be complete y << 
1833                  * is called), and we must no << 
1834                  * exception to this; see bel << 
1835                  */                           << 
1836                 if (req->work_scheduled) {    << 
1837                         req->work_need_resche << 
1838                 } else {                      << 
1839                         schedule_work(&req->w << 
1840                         req->work_scheduled = << 
1841                 }                             << 
1842                                               << 
1843                 /*                            << 
1844                  * If the waitqueue is being  << 
1845                  * the request inline, we hav << 
1846                  * we can.  That means immedi << 
1847                  * waitqueue and preventing a << 
1848                  * waitqueue via the request. << 
1849                  * completion work (done abov << 
1850                  * cancelled, to potentially  << 
1851                  */                           << 
1852                 if (mask & POLLFREE) {        << 
1853                         WRITE_ONCE(req->cance << 
1854                         list_del_init(&req->w << 
1855                                               << 
1856                         /*                    << 
1857                          * Careful: this *mus << 
1858                          * as req->head is NU << 
1859                          * completed and free << 
1860                          * will no longer nee << 
1861                          */                   << 
1862                         smp_store_release(&re << 
1863                 }                             << 
1864         }                                        1708         }
1865         return 1;                                1709         return 1;
1866 }                                                1710 }
1867                                                  1711 
1868 struct aio_poll_table {                          1712 struct aio_poll_table {
1869         struct poll_table_struct        pt;      1713         struct poll_table_struct        pt;
1870         struct aio_kiocb                *iocb    1714         struct aio_kiocb                *iocb;
1871         bool                            queue << 
1872         int                             error    1715         int                             error;
1873 };                                               1716 };
1874                                                  1717 
1875 static void                                      1718 static void
1876 aio_poll_queue_proc(struct file *file, struct    1719 aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
1877                 struct poll_table_struct *p)     1720                 struct poll_table_struct *p)
1878 {                                                1721 {
1879         struct aio_poll_table *pt = container    1722         struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
1880                                                  1723 
1881         /* multiple wait queues per file are     1724         /* multiple wait queues per file are not supported */
1882         if (unlikely(pt->queued)) {           !! 1725         if (unlikely(pt->iocb->poll.head)) {
1883                 pt->error = -EINVAL;             1726                 pt->error = -EINVAL;
1884                 return;                          1727                 return;
1885         }                                        1728         }
1886                                                  1729 
1887         pt->queued = true;                    << 
1888         pt->error = 0;                           1730         pt->error = 0;
1889         pt->iocb->poll.head = head;              1731         pt->iocb->poll.head = head;
1890         add_wait_queue(head, &pt->iocb->poll.    1732         add_wait_queue(head, &pt->iocb->poll.wait);
1891 }                                                1733 }
1892                                                  1734 
1893 static int aio_poll(struct aio_kiocb *aiocb,     1735 static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
1894 {                                                1736 {
1895         struct kioctx *ctx = aiocb->ki_ctx;      1737         struct kioctx *ctx = aiocb->ki_ctx;
1896         struct poll_iocb *req = &aiocb->poll;    1738         struct poll_iocb *req = &aiocb->poll;
1897         struct aio_poll_table apt;               1739         struct aio_poll_table apt;
1898         bool cancel = false;                     1740         bool cancel = false;
1899         __poll_t mask;                           1741         __poll_t mask;
1900                                                  1742 
1901         /* reject any unknown events outside     1743         /* reject any unknown events outside the normal event mask. */
1902         if ((u16)iocb->aio_buf != iocb->aio_b    1744         if ((u16)iocb->aio_buf != iocb->aio_buf)
1903                 return -EINVAL;                  1745                 return -EINVAL;
1904         /* reject fields that are not defined    1746         /* reject fields that are not defined for poll */
1905         if (iocb->aio_offset || iocb->aio_nby    1747         if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
1906                 return -EINVAL;                  1748                 return -EINVAL;
1907                                                  1749 
1908         INIT_WORK(&req->work, aio_poll_comple    1750         INIT_WORK(&req->work, aio_poll_complete_work);
1909         req->events = demangle_poll(iocb->aio    1751         req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
1910                                                  1752 
1911         req->head = NULL;                        1753         req->head = NULL;
                                                   >> 1754         req->done = false;
1912         req->cancelled = false;                  1755         req->cancelled = false;
1913         req->work_scheduled = false;          << 
1914         req->work_need_resched = false;       << 
1915                                                  1756 
1916         apt.pt._qproc = aio_poll_queue_proc;     1757         apt.pt._qproc = aio_poll_queue_proc;
1917         apt.pt._key = req->events;               1758         apt.pt._key = req->events;
1918         apt.iocb = aiocb;                        1759         apt.iocb = aiocb;
1919         apt.queued = false;                   << 
1920         apt.error = -EINVAL; /* same as no su    1760         apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
1921                                                  1761 
1922         /* initialized the list so that we ca    1762         /* initialized the list so that we can do list_empty checks */
1923         INIT_LIST_HEAD(&req->wait.entry);        1763         INIT_LIST_HEAD(&req->wait.entry);
1924         init_waitqueue_func_entry(&req->wait,    1764         init_waitqueue_func_entry(&req->wait, aio_poll_wake);
1925                                                  1765 
1926         mask = vfs_poll(req->file, &apt.pt) &    1766         mask = vfs_poll(req->file, &apt.pt) & req->events;
1927         spin_lock_irq(&ctx->ctx_lock);           1767         spin_lock_irq(&ctx->ctx_lock);
1928         if (likely(apt.queued)) {             !! 1768         if (likely(req->head)) {
1929                 bool on_queue = poll_iocb_loc !! 1769                 spin_lock(&req->head->lock);
1930                                               !! 1770                 if (unlikely(list_empty(&req->wait.entry))) {
1931                 if (!on_queue || req->work_sc !! 1771                         if (apt.error)
1932                         /*                    << 
1933                          * aio_poll_wake() al << 
1934                          * completion work, o << 
1935                          */                   << 
1936                         if (apt.error) /* uns << 
1937                                 cancel = true    1772                                 cancel = true;
1938                         apt.error = 0;           1773                         apt.error = 0;
1939                         mask = 0;                1774                         mask = 0;
1940                 }                                1775                 }
1941                 if (mask || apt.error) {         1776                 if (mask || apt.error) {
1942                         /* Steal to complete  << 
1943                         list_del_init(&req->w    1777                         list_del_init(&req->wait.entry);
1944                 } else if (cancel) {             1778                 } else if (cancel) {
1945                         /* Cancel if possible << 
1946                         WRITE_ONCE(req->cance    1779                         WRITE_ONCE(req->cancelled, true);
1947                 } else if (on_queue) {        !! 1780                 } else if (!req->done) { /* actually waiting for an event */
1948                         /*                    << 
1949                          * Actually waiting f << 
1950                          * active_reqs so tha << 
1951                          */                   << 
1952                         list_add_tail(&aiocb-    1781                         list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
1953                         aiocb->ki_cancel = ai    1782                         aiocb->ki_cancel = aio_poll_cancel;
1954                 }                                1783                 }
1955                 if (on_queue)                 !! 1784                 spin_unlock(&req->head->lock);
1956                         poll_iocb_unlock_wq(r << 
1957         }                                        1785         }
1958         if (mask) { /* no async, we'd stolen     1786         if (mask) { /* no async, we'd stolen it */
1959                 aiocb->ki_res.res = mangle_po    1787                 aiocb->ki_res.res = mangle_poll(mask);
1960                 apt.error = 0;                   1788                 apt.error = 0;
1961         }                                        1789         }
1962         spin_unlock_irq(&ctx->ctx_lock);         1790         spin_unlock_irq(&ctx->ctx_lock);
1963         if (mask)                                1791         if (mask)
1964                 iocb_put(aiocb);                 1792                 iocb_put(aiocb);
1965         return apt.error;                        1793         return apt.error;
1966 }                                                1794 }
1967                                                  1795 
1968 static int __io_submit_one(struct kioctx *ctx    1796 static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
1969                            struct iocb __user    1797                            struct iocb __user *user_iocb, struct aio_kiocb *req,
1970                            bool compat)          1798                            bool compat)
1971 {                                                1799 {
1972         req->ki_filp = fget(iocb->aio_fildes)    1800         req->ki_filp = fget(iocb->aio_fildes);
1973         if (unlikely(!req->ki_filp))             1801         if (unlikely(!req->ki_filp))
1974                 return -EBADF;                   1802                 return -EBADF;
1975                                                  1803 
1976         if (iocb->aio_flags & IOCB_FLAG_RESFD    1804         if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1977                 struct eventfd_ctx *eventfd;     1805                 struct eventfd_ctx *eventfd;
1978                 /*                               1806                 /*
1979                  * If the IOCB_FLAG_RESFD fla    1807                  * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1980                  * instance of the file* now.    1808                  * instance of the file* now. The file descriptor must be
1981                  * an eventfd() fd, and will     1809                  * an eventfd() fd, and will be signaled for each completed
1982                  * event using the eventfd_si    1810                  * event using the eventfd_signal() function.
1983                  */                              1811                  */
1984                 eventfd = eventfd_ctx_fdget(i    1812                 eventfd = eventfd_ctx_fdget(iocb->aio_resfd);
1985                 if (IS_ERR(eventfd))             1813                 if (IS_ERR(eventfd))
1986                         return PTR_ERR(eventf    1814                         return PTR_ERR(eventfd);
1987                                                  1815 
1988                 req->ki_eventfd = eventfd;       1816                 req->ki_eventfd = eventfd;
1989         }                                        1817         }
1990                                                  1818 
1991         if (unlikely(put_user(KIOCB_KEY, &use    1819         if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
1992                 pr_debug("EFAULT: aio_key\n")    1820                 pr_debug("EFAULT: aio_key\n");
1993                 return -EFAULT;                  1821                 return -EFAULT;
1994         }                                        1822         }
1995                                                  1823 
1996         req->ki_res.obj = (u64)(unsigned long    1824         req->ki_res.obj = (u64)(unsigned long)user_iocb;
1997         req->ki_res.data = iocb->aio_data;       1825         req->ki_res.data = iocb->aio_data;
1998         req->ki_res.res = 0;                     1826         req->ki_res.res = 0;
1999         req->ki_res.res2 = 0;                    1827         req->ki_res.res2 = 0;
2000                                                  1828 
2001         switch (iocb->aio_lio_opcode) {          1829         switch (iocb->aio_lio_opcode) {
2002         case IOCB_CMD_PREAD:                     1830         case IOCB_CMD_PREAD:
2003                 return aio_read(&req->rw, ioc    1831                 return aio_read(&req->rw, iocb, false, compat);
2004         case IOCB_CMD_PWRITE:                    1832         case IOCB_CMD_PWRITE:
2005                 return aio_write(&req->rw, io    1833                 return aio_write(&req->rw, iocb, false, compat);
2006         case IOCB_CMD_PREADV:                    1834         case IOCB_CMD_PREADV:
2007                 return aio_read(&req->rw, ioc    1835                 return aio_read(&req->rw, iocb, true, compat);
2008         case IOCB_CMD_PWRITEV:                   1836         case IOCB_CMD_PWRITEV:
2009                 return aio_write(&req->rw, io    1837                 return aio_write(&req->rw, iocb, true, compat);
2010         case IOCB_CMD_FSYNC:                     1838         case IOCB_CMD_FSYNC:
2011                 return aio_fsync(&req->fsync,    1839                 return aio_fsync(&req->fsync, iocb, false);
2012         case IOCB_CMD_FDSYNC:                    1840         case IOCB_CMD_FDSYNC:
2013                 return aio_fsync(&req->fsync,    1841                 return aio_fsync(&req->fsync, iocb, true);
2014         case IOCB_CMD_POLL:                      1842         case IOCB_CMD_POLL:
2015                 return aio_poll(req, iocb);      1843                 return aio_poll(req, iocb);
2016         default:                                 1844         default:
2017                 pr_debug("invalid aio operati    1845                 pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
2018                 return -EINVAL;                  1846                 return -EINVAL;
2019         }                                        1847         }
2020 }                                                1848 }
2021                                                  1849 
2022 static int io_submit_one(struct kioctx *ctx,     1850 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
2023                          bool compat)            1851                          bool compat)
2024 {                                                1852 {
2025         struct aio_kiocb *req;                   1853         struct aio_kiocb *req;
2026         struct iocb iocb;                        1854         struct iocb iocb;
2027         int err;                                 1855         int err;
2028                                                  1856 
2029         if (unlikely(copy_from_user(&iocb, us    1857         if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
2030                 return -EFAULT;                  1858                 return -EFAULT;
2031                                                  1859 
2032         /* enforce forwards compatibility on     1860         /* enforce forwards compatibility on users */
2033         if (unlikely(iocb.aio_reserved2)) {      1861         if (unlikely(iocb.aio_reserved2)) {
2034                 pr_debug("EINVAL: reserve fie    1862                 pr_debug("EINVAL: reserve field set\n");
2035                 return -EINVAL;                  1863                 return -EINVAL;
2036         }                                        1864         }
2037                                                  1865 
2038         /* prevent overflows */                  1866         /* prevent overflows */
2039         if (unlikely(                            1867         if (unlikely(
2040             (iocb.aio_buf != (unsigned long)i    1868             (iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
2041             (iocb.aio_nbytes != (size_t)iocb.    1869             (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
2042             ((ssize_t)iocb.aio_nbytes < 0)       1870             ((ssize_t)iocb.aio_nbytes < 0)
2043            )) {                                  1871            )) {
2044                 pr_debug("EINVAL: overflow ch    1872                 pr_debug("EINVAL: overflow check\n");
2045                 return -EINVAL;                  1873                 return -EINVAL;
2046         }                                        1874         }
2047                                                  1875 
2048         req = aio_get_req(ctx);                  1876         req = aio_get_req(ctx);
2049         if (unlikely(!req))                      1877         if (unlikely(!req))
2050                 return -EAGAIN;                  1878                 return -EAGAIN;
2051                                                  1879 
2052         err = __io_submit_one(ctx, &iocb, use    1880         err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
2053                                                  1881 
2054         /* Done with the synchronous referenc    1882         /* Done with the synchronous reference */
2055         iocb_put(req);                           1883         iocb_put(req);
2056                                                  1884 
2057         /*                                       1885         /*
2058          * If err is 0, we'd either done aio_    1886          * If err is 0, we'd either done aio_complete() ourselves or have
2059          * arranged for that to be done async    1887          * arranged for that to be done asynchronously.  Anything non-zero
2060          * means that we need to destroy req     1888          * means that we need to destroy req ourselves.
2061          */                                      1889          */
2062         if (unlikely(err)) {                     1890         if (unlikely(err)) {
2063                 iocb_destroy(req);               1891                 iocb_destroy(req);
2064                 put_reqs_available(ctx, 1);      1892                 put_reqs_available(ctx, 1);
2065         }                                        1893         }
2066         return err;                              1894         return err;
2067 }                                                1895 }
2068                                                  1896 
2069 /* sys_io_submit:                                1897 /* sys_io_submit:
2070  *      Queue the nr iocbs pointed to by iocb    1898  *      Queue the nr iocbs pointed to by iocbpp for processing.  Returns
2071  *      the number of iocbs queued.  May retu    1899  *      the number of iocbs queued.  May return -EINVAL if the aio_context
2072  *      specified by ctx_id is invalid, if nr    1900  *      specified by ctx_id is invalid, if nr is < 0, if the iocb at
2073  *      *iocbpp[0] is not properly initialize    1901  *      *iocbpp[0] is not properly initialized, if the operation specified
2074  *      is invalid for the file descriptor in    1902  *      is invalid for the file descriptor in the iocb.  May fail with
2075  *      -EFAULT if any of the data structures    1903  *      -EFAULT if any of the data structures point to invalid data.  May
2076  *      fail with -EBADF if the file descript    1904  *      fail with -EBADF if the file descriptor specified in the first
2077  *      iocb is invalid.  May fail with -EAGA    1905  *      iocb is invalid.  May fail with -EAGAIN if insufficient resources
2078  *      are available to queue any iocbs.  Wi    1906  *      are available to queue any iocbs.  Will return 0 if nr is 0.  Will
2079  *      fail with -ENOSYS if not implemented.    1907  *      fail with -ENOSYS if not implemented.
2080  */                                              1908  */
2081 SYSCALL_DEFINE3(io_submit, aio_context_t, ctx    1909 SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
2082                 struct iocb __user * __user *    1910                 struct iocb __user * __user *, iocbpp)
2083 {                                                1911 {
2084         struct kioctx *ctx;                      1912         struct kioctx *ctx;
2085         long ret = 0;                            1913         long ret = 0;
2086         int i = 0;                               1914         int i = 0;
2087         struct blk_plug plug;                    1915         struct blk_plug plug;
2088                                                  1916 
2089         if (unlikely(nr < 0))                    1917         if (unlikely(nr < 0))
2090                 return -EINVAL;                  1918                 return -EINVAL;
2091                                                  1919 
2092         ctx = lookup_ioctx(ctx_id);              1920         ctx = lookup_ioctx(ctx_id);
2093         if (unlikely(!ctx)) {                    1921         if (unlikely(!ctx)) {
2094                 pr_debug("EINVAL: invalid con    1922                 pr_debug("EINVAL: invalid context id\n");
2095                 return -EINVAL;                  1923                 return -EINVAL;
2096         }                                        1924         }
2097                                                  1925 
2098         if (nr > ctx->nr_events)                 1926         if (nr > ctx->nr_events)
2099                 nr = ctx->nr_events;             1927                 nr = ctx->nr_events;
2100                                                  1928 
2101         if (nr > AIO_PLUG_THRESHOLD)             1929         if (nr > AIO_PLUG_THRESHOLD)
2102                 blk_start_plug(&plug);           1930                 blk_start_plug(&plug);
2103         for (i = 0; i < nr; i++) {               1931         for (i = 0; i < nr; i++) {
2104                 struct iocb __user *user_iocb    1932                 struct iocb __user *user_iocb;
2105                                                  1933 
2106                 if (unlikely(get_user(user_io    1934                 if (unlikely(get_user(user_iocb, iocbpp + i))) {
2107                         ret = -EFAULT;           1935                         ret = -EFAULT;
2108                         break;                   1936                         break;
2109                 }                                1937                 }
2110                                                  1938 
2111                 ret = io_submit_one(ctx, user    1939                 ret = io_submit_one(ctx, user_iocb, false);
2112                 if (ret)                         1940                 if (ret)
2113                         break;                   1941                         break;
2114         }                                        1942         }
2115         if (nr > AIO_PLUG_THRESHOLD)             1943         if (nr > AIO_PLUG_THRESHOLD)
2116                 blk_finish_plug(&plug);          1944                 blk_finish_plug(&plug);
2117                                                  1945 
2118         percpu_ref_put(&ctx->users);             1946         percpu_ref_put(&ctx->users);
2119         return i ? i : ret;                      1947         return i ? i : ret;
2120 }                                                1948 }
2121                                                  1949 
2122 #ifdef CONFIG_COMPAT                             1950 #ifdef CONFIG_COMPAT
2123 COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_    1951 COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
2124                        int, nr, compat_uptr_t    1952                        int, nr, compat_uptr_t __user *, iocbpp)
2125 {                                                1953 {
2126         struct kioctx *ctx;                      1954         struct kioctx *ctx;
2127         long ret = 0;                            1955         long ret = 0;
2128         int i = 0;                               1956         int i = 0;
2129         struct blk_plug plug;                    1957         struct blk_plug plug;
2130                                                  1958 
2131         if (unlikely(nr < 0))                    1959         if (unlikely(nr < 0))
2132                 return -EINVAL;                  1960                 return -EINVAL;
2133                                                  1961 
2134         ctx = lookup_ioctx(ctx_id);              1962         ctx = lookup_ioctx(ctx_id);
2135         if (unlikely(!ctx)) {                    1963         if (unlikely(!ctx)) {
2136                 pr_debug("EINVAL: invalid con    1964                 pr_debug("EINVAL: invalid context id\n");
2137                 return -EINVAL;                  1965                 return -EINVAL;
2138         }                                        1966         }
2139                                                  1967 
2140         if (nr > ctx->nr_events)                 1968         if (nr > ctx->nr_events)
2141                 nr = ctx->nr_events;             1969                 nr = ctx->nr_events;
2142                                                  1970 
2143         if (nr > AIO_PLUG_THRESHOLD)             1971         if (nr > AIO_PLUG_THRESHOLD)
2144                 blk_start_plug(&plug);           1972                 blk_start_plug(&plug);
2145         for (i = 0; i < nr; i++) {               1973         for (i = 0; i < nr; i++) {
2146                 compat_uptr_t user_iocb;         1974                 compat_uptr_t user_iocb;
2147                                                  1975 
2148                 if (unlikely(get_user(user_io    1976                 if (unlikely(get_user(user_iocb, iocbpp + i))) {
2149                         ret = -EFAULT;           1977                         ret = -EFAULT;
2150                         break;                   1978                         break;
2151                 }                                1979                 }
2152                                                  1980 
2153                 ret = io_submit_one(ctx, comp    1981                 ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
2154                 if (ret)                         1982                 if (ret)
2155                         break;                   1983                         break;
2156         }                                        1984         }
2157         if (nr > AIO_PLUG_THRESHOLD)             1985         if (nr > AIO_PLUG_THRESHOLD)
2158                 blk_finish_plug(&plug);          1986                 blk_finish_plug(&plug);
2159                                                  1987 
2160         percpu_ref_put(&ctx->users);             1988         percpu_ref_put(&ctx->users);
2161         return i ? i : ret;                      1989         return i ? i : ret;
2162 }                                                1990 }
2163 #endif                                           1991 #endif
2164                                                  1992 
2165 /* sys_io_cancel:                                1993 /* sys_io_cancel:
2166  *      Attempts to cancel an iocb previously    1994  *      Attempts to cancel an iocb previously passed to io_submit.  If
2167  *      the operation is successfully cancell    1995  *      the operation is successfully cancelled, the resulting event is
2168  *      copied into the memory pointed to by     1996  *      copied into the memory pointed to by result without being placed
2169  *      into the completion queue and 0 is re    1997  *      into the completion queue and 0 is returned.  May fail with
2170  *      -EFAULT if any of the data structures    1998  *      -EFAULT if any of the data structures pointed to are invalid.
2171  *      May fail with -EINVAL if aio_context     1999  *      May fail with -EINVAL if aio_context specified by ctx_id is
2172  *      invalid.  May fail with -EAGAIN if th    2000  *      invalid.  May fail with -EAGAIN if the iocb specified was not
2173  *      cancelled.  Will fail with -ENOSYS if    2001  *      cancelled.  Will fail with -ENOSYS if not implemented.
2174  */                                              2002  */
2175 SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx    2003 SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
2176                 struct io_event __user *, res    2004                 struct io_event __user *, result)
2177 {                                                2005 {
2178         struct kioctx *ctx;                      2006         struct kioctx *ctx;
2179         struct aio_kiocb *kiocb;                 2007         struct aio_kiocb *kiocb;
2180         int ret = -EINVAL;                       2008         int ret = -EINVAL;
2181         u32 key;                                 2009         u32 key;
2182         u64 obj = (u64)(unsigned long)iocb;      2010         u64 obj = (u64)(unsigned long)iocb;
2183                                                  2011 
2184         if (unlikely(get_user(key, &iocb->aio    2012         if (unlikely(get_user(key, &iocb->aio_key)))
2185                 return -EFAULT;                  2013                 return -EFAULT;
2186         if (unlikely(key != KIOCB_KEY))          2014         if (unlikely(key != KIOCB_KEY))
2187                 return -EINVAL;                  2015                 return -EINVAL;
2188                                                  2016 
2189         ctx = lookup_ioctx(ctx_id);              2017         ctx = lookup_ioctx(ctx_id);
2190         if (unlikely(!ctx))                      2018         if (unlikely(!ctx))
2191                 return -EINVAL;                  2019                 return -EINVAL;
2192                                                  2020 
2193         spin_lock_irq(&ctx->ctx_lock);           2021         spin_lock_irq(&ctx->ctx_lock);
2194         /* TODO: use a hash or array, this su    2022         /* TODO: use a hash or array, this sucks. */
2195         list_for_each_entry(kiocb, &ctx->acti    2023         list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
2196                 if (kiocb->ki_res.obj == obj)    2024                 if (kiocb->ki_res.obj == obj) {
2197                         ret = kiocb->ki_cance    2025                         ret = kiocb->ki_cancel(&kiocb->rw);
2198                         list_del_init(&kiocb-    2026                         list_del_init(&kiocb->ki_list);
2199                         break;                   2027                         break;
2200                 }                                2028                 }
2201         }                                        2029         }
2202         spin_unlock_irq(&ctx->ctx_lock);         2030         spin_unlock_irq(&ctx->ctx_lock);
2203                                                  2031 
2204         if (!ret) {                              2032         if (!ret) {
2205                 /*                               2033                 /*
2206                  * The result argument is no     2034                  * The result argument is no longer used - the io_event is
2207                  * always delivered via the r    2035                  * always delivered via the ring buffer. -EINPROGRESS indicates
2208                  * cancellation is progress:     2036                  * cancellation is progress:
2209                  */                              2037                  */
2210                 ret = -EINPROGRESS;              2038                 ret = -EINPROGRESS;
2211         }                                        2039         }
2212                                                  2040 
2213         percpu_ref_put(&ctx->users);             2041         percpu_ref_put(&ctx->users);
2214                                                  2042 
2215         return ret;                              2043         return ret;
2216 }                                                2044 }
2217                                                  2045 
2218 static long do_io_getevents(aio_context_t ctx    2046 static long do_io_getevents(aio_context_t ctx_id,
2219                 long min_nr,                     2047                 long min_nr,
2220                 long nr,                         2048                 long nr,
2221                 struct io_event __user *event    2049                 struct io_event __user *events,
2222                 struct timespec64 *ts)           2050                 struct timespec64 *ts)
2223 {                                                2051 {
2224         ktime_t until = ts ? timespec64_to_kt    2052         ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
2225         struct kioctx *ioctx = lookup_ioctx(c    2053         struct kioctx *ioctx = lookup_ioctx(ctx_id);
2226         long ret = -EINVAL;                      2054         long ret = -EINVAL;
2227                                                  2055 
2228         if (likely(ioctx)) {                     2056         if (likely(ioctx)) {
2229                 if (likely(min_nr <= nr && mi    2057                 if (likely(min_nr <= nr && min_nr >= 0))
2230                         ret = read_events(ioc    2058                         ret = read_events(ioctx, min_nr, nr, events, until);
2231                 percpu_ref_put(&ioctx->users)    2059                 percpu_ref_put(&ioctx->users);
2232         }                                        2060         }
2233                                                  2061 
2234         return ret;                              2062         return ret;
2235 }                                                2063 }
2236                                                  2064 
2237 /* io_getevents:                                 2065 /* io_getevents:
2238  *      Attempts to read at least min_nr even    2066  *      Attempts to read at least min_nr events and up to nr events from
2239  *      the completion queue for the aio_cont    2067  *      the completion queue for the aio_context specified by ctx_id. If
2240  *      it succeeds, the number of read event    2068  *      it succeeds, the number of read events is returned. May fail with
2241  *      -EINVAL if ctx_id is invalid, if min_    2069  *      -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
2242  *      out of range, if timeout is out of ra    2070  *      out of range, if timeout is out of range.  May fail with -EFAULT
2243  *      if any of the memory specified is inv    2071  *      if any of the memory specified is invalid.  May return 0 or
2244  *      < min_nr if the timeout specified by     2072  *      < min_nr if the timeout specified by timeout has elapsed
2245  *      before sufficient events are availabl    2073  *      before sufficient events are available, where timeout == NULL
2246  *      specifies an infinite timeout. Note t    2074  *      specifies an infinite timeout. Note that the timeout pointed to by
2247  *      timeout is relative.  Will fail with     2075  *      timeout is relative.  Will fail with -ENOSYS if not implemented.
2248  */                                              2076  */
2249 #ifdef CONFIG_64BIT                              2077 #ifdef CONFIG_64BIT
2250                                                  2078 
2251 SYSCALL_DEFINE5(io_getevents, aio_context_t,     2079 SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
2252                 long, min_nr,                    2080                 long, min_nr,
2253                 long, nr,                        2081                 long, nr,
2254                 struct io_event __user *, eve    2082                 struct io_event __user *, events,
2255                 struct __kernel_timespec __us    2083                 struct __kernel_timespec __user *, timeout)
2256 {                                                2084 {
2257         struct timespec64       ts;              2085         struct timespec64       ts;
2258         int                     ret;             2086         int                     ret;
2259                                                  2087 
2260         if (timeout && unlikely(get_timespec6    2088         if (timeout && unlikely(get_timespec64(&ts, timeout)))
2261                 return -EFAULT;                  2089                 return -EFAULT;
2262                                                  2090 
2263         ret = do_io_getevents(ctx_id, min_nr,    2091         ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2264         if (!ret && signal_pending(current))     2092         if (!ret && signal_pending(current))
2265                 ret = -EINTR;                    2093                 ret = -EINTR;
2266         return ret;                              2094         return ret;
2267 }                                                2095 }
2268                                                  2096 
2269 #endif                                           2097 #endif
2270                                                  2098 
2271 struct __aio_sigset {                            2099 struct __aio_sigset {
2272         const sigset_t __user   *sigmask;        2100         const sigset_t __user   *sigmask;
2273         size_t          sigsetsize;              2101         size_t          sigsetsize;
2274 };                                               2102 };
2275                                                  2103 
2276 SYSCALL_DEFINE6(io_pgetevents,                   2104 SYSCALL_DEFINE6(io_pgetevents,
2277                 aio_context_t, ctx_id,           2105                 aio_context_t, ctx_id,
2278                 long, min_nr,                    2106                 long, min_nr,
2279                 long, nr,                        2107                 long, nr,
2280                 struct io_event __user *, eve    2108                 struct io_event __user *, events,
2281                 struct __kernel_timespec __us    2109                 struct __kernel_timespec __user *, timeout,
2282                 const struct __aio_sigset __u    2110                 const struct __aio_sigset __user *, usig)
2283 {                                                2111 {
2284         struct __aio_sigset     ksig = { NULL    2112         struct __aio_sigset     ksig = { NULL, };
2285         struct timespec64       ts;              2113         struct timespec64       ts;
2286         bool interrupted;                        2114         bool interrupted;
2287         int ret;                                 2115         int ret;
2288                                                  2116 
2289         if (timeout && unlikely(get_timespec6    2117         if (timeout && unlikely(get_timespec64(&ts, timeout)))
2290                 return -EFAULT;                  2118                 return -EFAULT;
2291                                                  2119 
2292         if (usig && copy_from_user(&ksig, usi    2120         if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2293                 return -EFAULT;                  2121                 return -EFAULT;
2294                                                  2122 
2295         ret = set_user_sigmask(ksig.sigmask,     2123         ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
2296         if (ret)                                 2124         if (ret)
2297                 return ret;                      2125                 return ret;
2298                                                  2126 
2299         ret = do_io_getevents(ctx_id, min_nr,    2127         ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2300                                                  2128 
2301         interrupted = signal_pending(current)    2129         interrupted = signal_pending(current);
2302         restore_saved_sigmask_unless(interrup    2130         restore_saved_sigmask_unless(interrupted);
2303         if (interrupted && !ret)                 2131         if (interrupted && !ret)
2304                 ret = -ERESTARTNOHAND;           2132                 ret = -ERESTARTNOHAND;
2305                                                  2133 
2306         return ret;                              2134         return ret;
2307 }                                                2135 }
2308                                                  2136 
2309 #if defined(CONFIG_COMPAT_32BIT_TIME) && !def    2137 #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
2310                                                  2138 
2311 SYSCALL_DEFINE6(io_pgetevents_time32,            2139 SYSCALL_DEFINE6(io_pgetevents_time32,
2312                 aio_context_t, ctx_id,           2140                 aio_context_t, ctx_id,
2313                 long, min_nr,                    2141                 long, min_nr,
2314                 long, nr,                        2142                 long, nr,
2315                 struct io_event __user *, eve    2143                 struct io_event __user *, events,
2316                 struct old_timespec32 __user     2144                 struct old_timespec32 __user *, timeout,
2317                 const struct __aio_sigset __u    2145                 const struct __aio_sigset __user *, usig)
2318 {                                                2146 {
2319         struct __aio_sigset     ksig = { NULL    2147         struct __aio_sigset     ksig = { NULL, };
2320         struct timespec64       ts;              2148         struct timespec64       ts;
2321         bool interrupted;                        2149         bool interrupted;
2322         int ret;                                 2150         int ret;
2323                                                  2151 
2324         if (timeout && unlikely(get_old_times    2152         if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
2325                 return -EFAULT;                  2153                 return -EFAULT;
2326                                                  2154 
2327         if (usig && copy_from_user(&ksig, usi    2155         if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2328                 return -EFAULT;                  2156                 return -EFAULT;
2329                                                  2157 
2330                                                  2158 
2331         ret = set_user_sigmask(ksig.sigmask,     2159         ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
2332         if (ret)                                 2160         if (ret)
2333                 return ret;                      2161                 return ret;
2334                                                  2162 
2335         ret = do_io_getevents(ctx_id, min_nr,    2163         ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2336                                                  2164 
2337         interrupted = signal_pending(current)    2165         interrupted = signal_pending(current);
2338         restore_saved_sigmask_unless(interrup    2166         restore_saved_sigmask_unless(interrupted);
2339         if (interrupted && !ret)                 2167         if (interrupted && !ret)
2340                 ret = -ERESTARTNOHAND;           2168                 ret = -ERESTARTNOHAND;
2341                                                  2169 
2342         return ret;                              2170         return ret;
2343 }                                                2171 }
2344                                                  2172 
2345 #endif                                           2173 #endif
2346                                                  2174 
2347 #if defined(CONFIG_COMPAT_32BIT_TIME)            2175 #if defined(CONFIG_COMPAT_32BIT_TIME)
2348                                                  2176 
2349 SYSCALL_DEFINE5(io_getevents_time32, __u32, c    2177 SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
2350                 __s32, min_nr,                   2178                 __s32, min_nr,
2351                 __s32, nr,                       2179                 __s32, nr,
2352                 struct io_event __user *, eve    2180                 struct io_event __user *, events,
2353                 struct old_timespec32 __user     2181                 struct old_timespec32 __user *, timeout)
2354 {                                                2182 {
2355         struct timespec64 t;                     2183         struct timespec64 t;
2356         int ret;                                 2184         int ret;
2357                                                  2185 
2358         if (timeout && get_old_timespec32(&t,    2186         if (timeout && get_old_timespec32(&t, timeout))
2359                 return -EFAULT;                  2187                 return -EFAULT;
2360                                                  2188 
2361         ret = do_io_getevents(ctx_id, min_nr,    2189         ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2362         if (!ret && signal_pending(current))     2190         if (!ret && signal_pending(current))
2363                 ret = -EINTR;                    2191                 ret = -EINTR;
2364         return ret;                              2192         return ret;
2365 }                                                2193 }
2366                                                  2194 
2367 #endif                                           2195 #endif
2368                                                  2196 
2369 #ifdef CONFIG_COMPAT                             2197 #ifdef CONFIG_COMPAT
2370                                                  2198 
2371 struct __compat_aio_sigset {                     2199 struct __compat_aio_sigset {
2372         compat_uptr_t           sigmask;         2200         compat_uptr_t           sigmask;
2373         compat_size_t           sigsetsize;      2201         compat_size_t           sigsetsize;
2374 };                                               2202 };
2375                                                  2203 
2376 #if defined(CONFIG_COMPAT_32BIT_TIME)            2204 #if defined(CONFIG_COMPAT_32BIT_TIME)
2377                                                  2205 
2378 COMPAT_SYSCALL_DEFINE6(io_pgetevents,            2206 COMPAT_SYSCALL_DEFINE6(io_pgetevents,
2379                 compat_aio_context_t, ctx_id,    2207                 compat_aio_context_t, ctx_id,
2380                 compat_long_t, min_nr,           2208                 compat_long_t, min_nr,
2381                 compat_long_t, nr,               2209                 compat_long_t, nr,
2382                 struct io_event __user *, eve    2210                 struct io_event __user *, events,
2383                 struct old_timespec32 __user     2211                 struct old_timespec32 __user *, timeout,
2384                 const struct __compat_aio_sig    2212                 const struct __compat_aio_sigset __user *, usig)
2385 {                                                2213 {
2386         struct __compat_aio_sigset ksig = { 0    2214         struct __compat_aio_sigset ksig = { 0, };
2387         struct timespec64 t;                     2215         struct timespec64 t;
2388         bool interrupted;                        2216         bool interrupted;
2389         int ret;                                 2217         int ret;
2390                                                  2218 
2391         if (timeout && get_old_timespec32(&t,    2219         if (timeout && get_old_timespec32(&t, timeout))
2392                 return -EFAULT;                  2220                 return -EFAULT;
2393                                                  2221 
2394         if (usig && copy_from_user(&ksig, usi    2222         if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2395                 return -EFAULT;                  2223                 return -EFAULT;
2396                                                  2224 
2397         ret = set_compat_user_sigmask(compat_    2225         ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
2398         if (ret)                                 2226         if (ret)
2399                 return ret;                      2227                 return ret;
2400                                                  2228 
2401         ret = do_io_getevents(ctx_id, min_nr,    2229         ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2402                                                  2230 
2403         interrupted = signal_pending(current)    2231         interrupted = signal_pending(current);
2404         restore_saved_sigmask_unless(interrup    2232         restore_saved_sigmask_unless(interrupted);
2405         if (interrupted && !ret)                 2233         if (interrupted && !ret)
2406                 ret = -ERESTARTNOHAND;           2234                 ret = -ERESTARTNOHAND;
2407                                                  2235 
2408         return ret;                              2236         return ret;
2409 }                                                2237 }
2410                                                  2238 
2411 #endif                                           2239 #endif
2412                                                  2240 
2413 COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,     2241 COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
2414                 compat_aio_context_t, ctx_id,    2242                 compat_aio_context_t, ctx_id,
2415                 compat_long_t, min_nr,           2243                 compat_long_t, min_nr,
2416                 compat_long_t, nr,               2244                 compat_long_t, nr,
2417                 struct io_event __user *, eve    2245                 struct io_event __user *, events,
2418                 struct __kernel_timespec __us    2246                 struct __kernel_timespec __user *, timeout,
2419                 const struct __compat_aio_sig    2247                 const struct __compat_aio_sigset __user *, usig)
2420 {                                                2248 {
2421         struct __compat_aio_sigset ksig = { 0    2249         struct __compat_aio_sigset ksig = { 0, };
2422         struct timespec64 t;                     2250         struct timespec64 t;
2423         bool interrupted;                        2251         bool interrupted;
2424         int ret;                                 2252         int ret;
2425                                                  2253 
2426         if (timeout && get_timespec64(&t, tim    2254         if (timeout && get_timespec64(&t, timeout))
2427                 return -EFAULT;                  2255                 return -EFAULT;
2428                                                  2256 
2429         if (usig && copy_from_user(&ksig, usi    2257         if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2430                 return -EFAULT;                  2258                 return -EFAULT;
2431                                                  2259 
2432         ret = set_compat_user_sigmask(compat_    2260         ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
2433         if (ret)                                 2261         if (ret)
2434                 return ret;                      2262                 return ret;
2435                                                  2263 
2436         ret = do_io_getevents(ctx_id, min_nr,    2264         ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2437                                                  2265 
2438         interrupted = signal_pending(current)    2266         interrupted = signal_pending(current);
2439         restore_saved_sigmask_unless(interrup    2267         restore_saved_sigmask_unless(interrupted);
2440         if (interrupted && !ret)                 2268         if (interrupted && !ret)
2441                 ret = -ERESTARTNOHAND;           2269                 ret = -ERESTARTNOHAND;
2442                                                  2270 
2443         return ret;                              2271         return ret;
2444 }                                                2272 }
2445 #endif                                           2273 #endif
2446                                                  2274 

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