1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/fs.h>
5 #include <linux/file.h>
6 #include <linux/mm.h>
7 #include <linux/slab.h>
8 #include <linux/nospec.h>
9 #include <linux/hugetlb.h>
10 #include <linux/compat.h>
11 #include <linux/io_uring.h>
12
13 #include <uapi/linux/io_uring.h>
14
15 #include "io_uring.h"
16 #include "alloc_cache.h"
17 #include "openclose.h"
18 #include "rsrc.h"
19 #include "memmap.h"
20
21 struct io_rsrc_update {
22 struct file *file;
23 u64 arg;
24 u32 nr_args;
25 u32 offset;
26 };
27
28 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
29 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
30 struct io_mapped_ubuf **pimu,
31 struct page **last_hpage);
32
33 /* only define max */
34 #define IORING_MAX_FIXED_FILES (1U << 20)
35 #define IORING_MAX_REG_BUFFERS (1U << 14)
36
37 static const struct io_mapped_ubuf dummy_ubuf = {
38 /* set invalid range, so io_import_fixed() fails meeting it */
39 .ubuf = -1UL,
40 .ubuf_end = 0,
41 };
42
43 int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
44 {
45 unsigned long page_limit, cur_pages, new_pages;
46
47 if (!nr_pages)
48 return 0;
49
50 /* Don't allow more pages than we can safely lock */
51 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
52
53 cur_pages = atomic_long_read(&user->locked_vm);
54 do {
55 new_pages = cur_pages + nr_pages;
56 if (new_pages > page_limit)
57 return -ENOMEM;
58 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
59 &cur_pages, new_pages));
60 return 0;
61 }
62
63 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
64 {
65 if (ctx->user)
66 __io_unaccount_mem(ctx->user, nr_pages);
67
68 if (ctx->mm_account)
69 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
70 }
71
72 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
73 {
74 int ret;
75
76 if (ctx->user) {
77 ret = __io_account_mem(ctx->user, nr_pages);
78 if (ret)
79 return ret;
80 }
81
82 if (ctx->mm_account)
83 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
84
85 return 0;
86 }
87
88 static int io_buffer_validate(struct iovec *iov)
89 {
90 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
91
92 /*
93 * Don't impose further limits on the size and buffer
94 * constraints here, we'll -EINVAL later when IO is
95 * submitted if they are wrong.
96 */
97 if (!iov->iov_base)
98 return iov->iov_len ? -EFAULT : 0;
99 if (!iov->iov_len)
100 return -EFAULT;
101
102 /* arbitrary limit, but we need something */
103 if (iov->iov_len > SZ_1G)
104 return -EFAULT;
105
106 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
107 return -EOVERFLOW;
108
109 return 0;
110 }
111
112 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
113 {
114 struct io_mapped_ubuf *imu = *slot;
115 unsigned int i;
116
117 if (imu != &dummy_ubuf) {
118 for (i = 0; i < imu->nr_bvecs; i++)
119 unpin_user_page(imu->bvec[i].bv_page);
120 if (imu->acct_pages)
121 io_unaccount_mem(ctx, imu->acct_pages);
122 kvfree(imu);
123 }
124 *slot = NULL;
125 }
126
127 static void io_rsrc_put_work(struct io_rsrc_node *node)
128 {
129 struct io_rsrc_put *prsrc = &node->item;
130
131 if (prsrc->tag)
132 io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0);
133
134 switch (node->type) {
135 case IORING_RSRC_FILE:
136 fput(prsrc->file);
137 break;
138 case IORING_RSRC_BUFFER:
139 io_rsrc_buf_put(node->ctx, prsrc);
140 break;
141 default:
142 WARN_ON_ONCE(1);
143 break;
144 }
145 }
146
147 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
148 {
149 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, node))
150 kfree(node);
151 }
152
153 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
154 __must_hold(&node->ctx->uring_lock)
155 {
156 struct io_ring_ctx *ctx = node->ctx;
157
158 while (!list_empty(&ctx->rsrc_ref_list)) {
159 node = list_first_entry(&ctx->rsrc_ref_list,
160 struct io_rsrc_node, node);
161 /* recycle ref nodes in order */
162 if (node->refs)
163 break;
164 list_del(&node->node);
165
166 if (likely(!node->empty))
167 io_rsrc_put_work(node);
168 io_rsrc_node_destroy(ctx, node);
169 }
170 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
171 wake_up_all(&ctx->rsrc_quiesce_wq);
172 }
173
174 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
175 {
176 struct io_rsrc_node *ref_node;
177
178 ref_node = io_alloc_cache_get(&ctx->rsrc_node_cache);
179 if (!ref_node) {
180 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
181 if (!ref_node)
182 return NULL;
183 }
184
185 ref_node->ctx = ctx;
186 ref_node->empty = 0;
187 ref_node->refs = 1;
188 return ref_node;
189 }
190
191 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
192 struct io_ring_ctx *ctx)
193 {
194 struct io_rsrc_node *backup;
195 DEFINE_WAIT(we);
196 int ret;
197
198 /* As We may drop ->uring_lock, other task may have started quiesce */
199 if (data->quiesce)
200 return -ENXIO;
201
202 backup = io_rsrc_node_alloc(ctx);
203 if (!backup)
204 return -ENOMEM;
205 ctx->rsrc_node->empty = true;
206 ctx->rsrc_node->type = -1;
207 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
208 io_put_rsrc_node(ctx, ctx->rsrc_node);
209 ctx->rsrc_node = backup;
210
211 if (list_empty(&ctx->rsrc_ref_list))
212 return 0;
213
214 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
215 atomic_set(&ctx->cq_wait_nr, 1);
216 smp_mb();
217 }
218
219 ctx->rsrc_quiesce++;
220 data->quiesce = true;
221 do {
222 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
223 mutex_unlock(&ctx->uring_lock);
224
225 ret = io_run_task_work_sig(ctx);
226 if (ret < 0) {
227 finish_wait(&ctx->rsrc_quiesce_wq, &we);
228 mutex_lock(&ctx->uring_lock);
229 if (list_empty(&ctx->rsrc_ref_list))
230 ret = 0;
231 break;
232 }
233
234 schedule();
235 mutex_lock(&ctx->uring_lock);
236 ret = 0;
237 } while (!list_empty(&ctx->rsrc_ref_list));
238
239 finish_wait(&ctx->rsrc_quiesce_wq, &we);
240 data->quiesce = false;
241 ctx->rsrc_quiesce--;
242
243 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
244 atomic_set(&ctx->cq_wait_nr, 0);
245 smp_mb();
246 }
247 return ret;
248 }
249
250 static void io_free_page_table(void **table, size_t size)
251 {
252 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
253
254 for (i = 0; i < nr_tables; i++)
255 kfree(table[i]);
256 kfree(table);
257 }
258
259 static void io_rsrc_data_free(struct io_rsrc_data *data)
260 {
261 size_t size = data->nr * sizeof(data->tags[0][0]);
262
263 if (data->tags)
264 io_free_page_table((void **)data->tags, size);
265 kfree(data);
266 }
267
268 static __cold void **io_alloc_page_table(size_t size)
269 {
270 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
271 size_t init_size = size;
272 void **table;
273
274 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
275 if (!table)
276 return NULL;
277
278 for (i = 0; i < nr_tables; i++) {
279 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
280
281 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
282 if (!table[i]) {
283 io_free_page_table(table, init_size);
284 return NULL;
285 }
286 size -= this_size;
287 }
288 return table;
289 }
290
291 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type,
292 u64 __user *utags,
293 unsigned nr, struct io_rsrc_data **pdata)
294 {
295 struct io_rsrc_data *data;
296 int ret = 0;
297 unsigned i;
298
299 data = kzalloc(sizeof(*data), GFP_KERNEL);
300 if (!data)
301 return -ENOMEM;
302 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
303 if (!data->tags) {
304 kfree(data);
305 return -ENOMEM;
306 }
307
308 data->nr = nr;
309 data->ctx = ctx;
310 data->rsrc_type = type;
311 if (utags) {
312 ret = -EFAULT;
313 for (i = 0; i < nr; i++) {
314 u64 *tag_slot = io_get_tag_slot(data, i);
315
316 if (copy_from_user(tag_slot, &utags[i],
317 sizeof(*tag_slot)))
318 goto fail;
319 }
320 }
321 *pdata = data;
322 return 0;
323 fail:
324 io_rsrc_data_free(data);
325 return ret;
326 }
327
328 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
329 struct io_uring_rsrc_update2 *up,
330 unsigned nr_args)
331 {
332 u64 __user *tags = u64_to_user_ptr(up->tags);
333 __s32 __user *fds = u64_to_user_ptr(up->data);
334 struct io_rsrc_data *data = ctx->file_data;
335 struct io_fixed_file *file_slot;
336 int fd, i, err = 0;
337 unsigned int done;
338
339 if (!ctx->file_data)
340 return -ENXIO;
341 if (up->offset + nr_args > ctx->nr_user_files)
342 return -EINVAL;
343
344 for (done = 0; done < nr_args; done++) {
345 u64 tag = 0;
346
347 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
348 copy_from_user(&fd, &fds[done], sizeof(fd))) {
349 err = -EFAULT;
350 break;
351 }
352 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
353 err = -EINVAL;
354 break;
355 }
356 if (fd == IORING_REGISTER_FILES_SKIP)
357 continue;
358
359 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
360 file_slot = io_fixed_file_slot(&ctx->file_table, i);
361
362 if (file_slot->file_ptr) {
363 err = io_queue_rsrc_removal(data, i,
364 io_slot_file(file_slot));
365 if (err)
366 break;
367 file_slot->file_ptr = 0;
368 io_file_bitmap_clear(&ctx->file_table, i);
369 }
370 if (fd != -1) {
371 struct file *file = fget(fd);
372
373 if (!file) {
374 err = -EBADF;
375 break;
376 }
377 /*
378 * Don't allow io_uring instances to be registered.
379 */
380 if (io_is_uring_fops(file)) {
381 fput(file);
382 err = -EBADF;
383 break;
384 }
385 *io_get_tag_slot(data, i) = tag;
386 io_fixed_file_set(file_slot, file);
387 io_file_bitmap_set(&ctx->file_table, i);
388 }
389 }
390 return done ? done : err;
391 }
392
393 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
394 struct io_uring_rsrc_update2 *up,
395 unsigned int nr_args)
396 {
397 u64 __user *tags = u64_to_user_ptr(up->tags);
398 struct iovec fast_iov, *iov;
399 struct page *last_hpage = NULL;
400 struct iovec __user *uvec;
401 u64 user_data = up->data;
402 __u32 done;
403 int i, err;
404
405 if (!ctx->buf_data)
406 return -ENXIO;
407 if (up->offset + nr_args > ctx->nr_user_bufs)
408 return -EINVAL;
409
410 for (done = 0; done < nr_args; done++) {
411 struct io_mapped_ubuf *imu;
412 u64 tag = 0;
413
414 uvec = u64_to_user_ptr(user_data);
415 iov = iovec_from_user(uvec, 1, 1, &fast_iov, ctx->compat);
416 if (IS_ERR(iov)) {
417 err = PTR_ERR(iov);
418 break;
419 }
420 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
421 err = -EFAULT;
422 break;
423 }
424 err = io_buffer_validate(iov);
425 if (err)
426 break;
427 if (!iov->iov_base && tag) {
428 err = -EINVAL;
429 break;
430 }
431 err = io_sqe_buffer_register(ctx, iov, &imu, &last_hpage);
432 if (err)
433 break;
434
435 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
436 if (ctx->user_bufs[i] != &dummy_ubuf) {
437 err = io_queue_rsrc_removal(ctx->buf_data, i,
438 ctx->user_bufs[i]);
439 if (unlikely(err)) {
440 io_buffer_unmap(ctx, &imu);
441 break;
442 }
443 ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf;
444 }
445
446 ctx->user_bufs[i] = imu;
447 *io_get_tag_slot(ctx->buf_data, i) = tag;
448 if (ctx->compat)
449 user_data += sizeof(struct compat_iovec);
450 else
451 user_data += sizeof(struct iovec);
452 }
453 return done ? done : err;
454 }
455
456 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
457 struct io_uring_rsrc_update2 *up,
458 unsigned nr_args)
459 {
460 __u32 tmp;
461
462 lockdep_assert_held(&ctx->uring_lock);
463
464 if (check_add_overflow(up->offset, nr_args, &tmp))
465 return -EOVERFLOW;
466
467 switch (type) {
468 case IORING_RSRC_FILE:
469 return __io_sqe_files_update(ctx, up, nr_args);
470 case IORING_RSRC_BUFFER:
471 return __io_sqe_buffers_update(ctx, up, nr_args);
472 }
473 return -EINVAL;
474 }
475
476 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
477 unsigned nr_args)
478 {
479 struct io_uring_rsrc_update2 up;
480
481 if (!nr_args)
482 return -EINVAL;
483 memset(&up, 0, sizeof(up));
484 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
485 return -EFAULT;
486 if (up.resv || up.resv2)
487 return -EINVAL;
488 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
489 }
490
491 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
492 unsigned size, unsigned type)
493 {
494 struct io_uring_rsrc_update2 up;
495
496 if (size != sizeof(up))
497 return -EINVAL;
498 if (copy_from_user(&up, arg, sizeof(up)))
499 return -EFAULT;
500 if (!up.nr || up.resv || up.resv2)
501 return -EINVAL;
502 return __io_register_rsrc_update(ctx, type, &up, up.nr);
503 }
504
505 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
506 unsigned int size, unsigned int type)
507 {
508 struct io_uring_rsrc_register rr;
509
510 /* keep it extendible */
511 if (size != sizeof(rr))
512 return -EINVAL;
513
514 memset(&rr, 0, sizeof(rr));
515 if (copy_from_user(&rr, arg, size))
516 return -EFAULT;
517 if (!rr.nr || rr.resv2)
518 return -EINVAL;
519 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
520 return -EINVAL;
521
522 switch (type) {
523 case IORING_RSRC_FILE:
524 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
525 break;
526 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
527 rr.nr, u64_to_user_ptr(rr.tags));
528 case IORING_RSRC_BUFFER:
529 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
530 break;
531 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
532 rr.nr, u64_to_user_ptr(rr.tags));
533 }
534 return -EINVAL;
535 }
536
537 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
538 {
539 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
540
541 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
542 return -EINVAL;
543 if (sqe->rw_flags || sqe->splice_fd_in)
544 return -EINVAL;
545
546 up->offset = READ_ONCE(sqe->off);
547 up->nr_args = READ_ONCE(sqe->len);
548 if (!up->nr_args)
549 return -EINVAL;
550 up->arg = READ_ONCE(sqe->addr);
551 return 0;
552 }
553
554 static int io_files_update_with_index_alloc(struct io_kiocb *req,
555 unsigned int issue_flags)
556 {
557 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
558 __s32 __user *fds = u64_to_user_ptr(up->arg);
559 unsigned int done;
560 struct file *file;
561 int ret, fd;
562
563 if (!req->ctx->file_data)
564 return -ENXIO;
565
566 for (done = 0; done < up->nr_args; done++) {
567 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
568 ret = -EFAULT;
569 break;
570 }
571
572 file = fget(fd);
573 if (!file) {
574 ret = -EBADF;
575 break;
576 }
577 ret = io_fixed_fd_install(req, issue_flags, file,
578 IORING_FILE_INDEX_ALLOC);
579 if (ret < 0)
580 break;
581 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
582 __io_close_fixed(req->ctx, issue_flags, ret);
583 ret = -EFAULT;
584 break;
585 }
586 }
587
588 if (done)
589 return done;
590 return ret;
591 }
592
593 int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
594 {
595 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
596 struct io_ring_ctx *ctx = req->ctx;
597 struct io_uring_rsrc_update2 up2;
598 int ret;
599
600 up2.offset = up->offset;
601 up2.data = up->arg;
602 up2.nr = 0;
603 up2.tags = 0;
604 up2.resv = 0;
605 up2.resv2 = 0;
606
607 if (up->offset == IORING_FILE_INDEX_ALLOC) {
608 ret = io_files_update_with_index_alloc(req, issue_flags);
609 } else {
610 io_ring_submit_lock(ctx, issue_flags);
611 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
612 &up2, up->nr_args);
613 io_ring_submit_unlock(ctx, issue_flags);
614 }
615
616 if (ret < 0)
617 req_set_fail(req);
618 io_req_set_res(req, ret, 0);
619 return IOU_OK;
620 }
621
622 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
623 {
624 struct io_ring_ctx *ctx = data->ctx;
625 struct io_rsrc_node *node = ctx->rsrc_node;
626 u64 *tag_slot = io_get_tag_slot(data, idx);
627
628 ctx->rsrc_node = io_rsrc_node_alloc(ctx);
629 if (unlikely(!ctx->rsrc_node)) {
630 ctx->rsrc_node = node;
631 return -ENOMEM;
632 }
633
634 node->item.rsrc = rsrc;
635 node->type = data->rsrc_type;
636 node->item.tag = *tag_slot;
637 *tag_slot = 0;
638 list_add_tail(&node->node, &ctx->rsrc_ref_list);
639 io_put_rsrc_node(ctx, node);
640 return 0;
641 }
642
643 void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
644 {
645 int i;
646
647 for (i = 0; i < ctx->nr_user_files; i++) {
648 struct file *file = io_file_from_index(&ctx->file_table, i);
649
650 if (!file)
651 continue;
652 io_file_bitmap_clear(&ctx->file_table, i);
653 fput(file);
654 }
655
656 io_free_file_tables(&ctx->file_table);
657 io_file_table_set_alloc_range(ctx, 0, 0);
658 io_rsrc_data_free(ctx->file_data);
659 ctx->file_data = NULL;
660 ctx->nr_user_files = 0;
661 }
662
663 int io_sqe_files_unregister(struct io_ring_ctx *ctx)
664 {
665 unsigned nr = ctx->nr_user_files;
666 int ret;
667
668 if (!ctx->file_data)
669 return -ENXIO;
670
671 /*
672 * Quiesce may unlock ->uring_lock, and while it's not held
673 * prevent new requests using the table.
674 */
675 ctx->nr_user_files = 0;
676 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
677 ctx->nr_user_files = nr;
678 if (!ret)
679 __io_sqe_files_unregister(ctx);
680 return ret;
681 }
682
683 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
684 unsigned nr_args, u64 __user *tags)
685 {
686 __s32 __user *fds = (__s32 __user *) arg;
687 struct file *file;
688 int fd, ret;
689 unsigned i;
690
691 if (ctx->file_data)
692 return -EBUSY;
693 if (!nr_args)
694 return -EINVAL;
695 if (nr_args > IORING_MAX_FIXED_FILES)
696 return -EMFILE;
697 if (nr_args > rlimit(RLIMIT_NOFILE))
698 return -EMFILE;
699 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args,
700 &ctx->file_data);
701 if (ret)
702 return ret;
703
704 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
705 io_rsrc_data_free(ctx->file_data);
706 ctx->file_data = NULL;
707 return -ENOMEM;
708 }
709
710 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
711 struct io_fixed_file *file_slot;
712
713 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
714 ret = -EFAULT;
715 goto fail;
716 }
717 /* allow sparse sets */
718 if (!fds || fd == -1) {
719 ret = -EINVAL;
720 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
721 goto fail;
722 continue;
723 }
724
725 file = fget(fd);
726 ret = -EBADF;
727 if (unlikely(!file))
728 goto fail;
729
730 /*
731 * Don't allow io_uring instances to be registered.
732 */
733 if (io_is_uring_fops(file)) {
734 fput(file);
735 goto fail;
736 }
737 file_slot = io_fixed_file_slot(&ctx->file_table, i);
738 io_fixed_file_set(file_slot, file);
739 io_file_bitmap_set(&ctx->file_table, i);
740 }
741
742 /* default it to the whole table */
743 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
744 return 0;
745 fail:
746 __io_sqe_files_unregister(ctx);
747 return ret;
748 }
749
750 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
751 {
752 io_buffer_unmap(ctx, &prsrc->buf);
753 prsrc->buf = NULL;
754 }
755
756 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
757 {
758 unsigned int i;
759
760 for (i = 0; i < ctx->nr_user_bufs; i++)
761 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
762 kfree(ctx->user_bufs);
763 io_rsrc_data_free(ctx->buf_data);
764 ctx->user_bufs = NULL;
765 ctx->buf_data = NULL;
766 ctx->nr_user_bufs = 0;
767 }
768
769 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
770 {
771 unsigned nr = ctx->nr_user_bufs;
772 int ret;
773
774 if (!ctx->buf_data)
775 return -ENXIO;
776
777 /*
778 * Quiesce may unlock ->uring_lock, and while it's not held
779 * prevent new requests using the table.
780 */
781 ctx->nr_user_bufs = 0;
782 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
783 ctx->nr_user_bufs = nr;
784 if (!ret)
785 __io_sqe_buffers_unregister(ctx);
786 return ret;
787 }
788
789 /*
790 * Not super efficient, but this is just a registration time. And we do cache
791 * the last compound head, so generally we'll only do a full search if we don't
792 * match that one.
793 *
794 * We check if the given compound head page has already been accounted, to
795 * avoid double accounting it. This allows us to account the full size of the
796 * page, not just the constituent pages of a huge page.
797 */
798 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
799 int nr_pages, struct page *hpage)
800 {
801 int i, j;
802
803 /* check current page array */
804 for (i = 0; i < nr_pages; i++) {
805 if (!PageCompound(pages[i]))
806 continue;
807 if (compound_head(pages[i]) == hpage)
808 return true;
809 }
810
811 /* check previously registered pages */
812 for (i = 0; i < ctx->nr_user_bufs; i++) {
813 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
814
815 for (j = 0; j < imu->nr_bvecs; j++) {
816 if (!PageCompound(imu->bvec[j].bv_page))
817 continue;
818 if (compound_head(imu->bvec[j].bv_page) == hpage)
819 return true;
820 }
821 }
822
823 return false;
824 }
825
826 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
827 int nr_pages, struct io_mapped_ubuf *imu,
828 struct page **last_hpage)
829 {
830 int i, ret;
831
832 imu->acct_pages = 0;
833 for (i = 0; i < nr_pages; i++) {
834 if (!PageCompound(pages[i])) {
835 imu->acct_pages++;
836 } else {
837 struct page *hpage;
838
839 hpage = compound_head(pages[i]);
840 if (hpage == *last_hpage)
841 continue;
842 *last_hpage = hpage;
843 if (headpage_already_acct(ctx, pages, i, hpage))
844 continue;
845 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
846 }
847 }
848
849 if (!imu->acct_pages)
850 return 0;
851
852 ret = io_account_mem(ctx, imu->acct_pages);
853 if (ret)
854 imu->acct_pages = 0;
855 return ret;
856 }
857
858 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
859 struct io_mapped_ubuf **pimu,
860 struct page **last_hpage)
861 {
862 struct io_mapped_ubuf *imu = NULL;
863 struct page **pages = NULL;
864 unsigned long off;
865 size_t size;
866 int ret, nr_pages, i;
867 struct folio *folio = NULL;
868
869 *pimu = (struct io_mapped_ubuf *)&dummy_ubuf;
870 if (!iov->iov_base)
871 return 0;
872
873 ret = -ENOMEM;
874 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
875 &nr_pages);
876 if (IS_ERR(pages)) {
877 ret = PTR_ERR(pages);
878 pages = NULL;
879 goto done;
880 }
881
882 /* If it's a huge page, try to coalesce them into a single bvec entry */
883 if (nr_pages > 1) {
884 folio = page_folio(pages[0]);
885 for (i = 1; i < nr_pages; i++) {
886 /*
887 * Pages must be consecutive and on the same folio for
888 * this to work
889 */
890 if (page_folio(pages[i]) != folio ||
891 pages[i] != pages[i - 1] + 1) {
892 folio = NULL;
893 break;
894 }
895 }
896 if (folio) {
897 /*
898 * The pages are bound to the folio, it doesn't
899 * actually unpin them but drops all but one reference,
900 * which is usually put down by io_buffer_unmap().
901 * Note, needs a better helper.
902 */
903 unpin_user_pages(&pages[1], nr_pages - 1);
904 nr_pages = 1;
905 }
906 }
907
908 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
909 if (!imu)
910 goto done;
911
912 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
913 if (ret) {
914 unpin_user_pages(pages, nr_pages);
915 goto done;
916 }
917
918 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
919 size = iov->iov_len;
920 /* store original address for later verification */
921 imu->ubuf = (unsigned long) iov->iov_base;
922 imu->ubuf_end = imu->ubuf + iov->iov_len;
923 imu->nr_bvecs = nr_pages;
924 *pimu = imu;
925 ret = 0;
926
927 if (folio) {
928 bvec_set_page(&imu->bvec[0], pages[0], size, off);
929 goto done;
930 }
931 for (i = 0; i < nr_pages; i++) {
932 size_t vec_len;
933
934 vec_len = min_t(size_t, size, PAGE_SIZE - off);
935 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
936 off = 0;
937 size -= vec_len;
938 }
939 done:
940 if (ret)
941 kvfree(imu);
942 kvfree(pages);
943 return ret;
944 }
945
946 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
947 {
948 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
949 return ctx->user_bufs ? 0 : -ENOMEM;
950 }
951
952 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
953 unsigned int nr_args, u64 __user *tags)
954 {
955 struct page *last_hpage = NULL;
956 struct io_rsrc_data *data;
957 struct iovec fast_iov, *iov = &fast_iov;
958 const struct iovec __user *uvec;
959 int i, ret;
960
961 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
962
963 if (ctx->user_bufs)
964 return -EBUSY;
965 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
966 return -EINVAL;
967 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data);
968 if (ret)
969 return ret;
970 ret = io_buffers_map_alloc(ctx, nr_args);
971 if (ret) {
972 io_rsrc_data_free(data);
973 return ret;
974 }
975
976 if (!arg)
977 memset(iov, 0, sizeof(*iov));
978
979 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
980 if (arg) {
981 uvec = (struct iovec __user *) arg;
982 iov = iovec_from_user(uvec, 1, 1, &fast_iov, ctx->compat);
983 if (IS_ERR(iov)) {
984 ret = PTR_ERR(iov);
985 break;
986 }
987 ret = io_buffer_validate(iov);
988 if (ret)
989 break;
990 if (ctx->compat)
991 arg += sizeof(struct compat_iovec);
992 else
993 arg += sizeof(struct iovec);
994 }
995
996 if (!iov->iov_base && *io_get_tag_slot(data, i)) {
997 ret = -EINVAL;
998 break;
999 }
1000
1001 ret = io_sqe_buffer_register(ctx, iov, &ctx->user_bufs[i],
1002 &last_hpage);
1003 if (ret)
1004 break;
1005 }
1006
1007 WARN_ON_ONCE(ctx->buf_data);
1008
1009 ctx->buf_data = data;
1010 if (ret)
1011 __io_sqe_buffers_unregister(ctx);
1012 return ret;
1013 }
1014
1015 int io_import_fixed(int ddir, struct iov_iter *iter,
1016 struct io_mapped_ubuf *imu,
1017 u64 buf_addr, size_t len)
1018 {
1019 u64 buf_end;
1020 size_t offset;
1021
1022 if (WARN_ON_ONCE(!imu))
1023 return -EFAULT;
1024 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1025 return -EFAULT;
1026 /* not inside the mapped region */
1027 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1028 return -EFAULT;
1029
1030 /*
1031 * Might not be a start of buffer, set size appropriately
1032 * and advance us to the beginning.
1033 */
1034 offset = buf_addr - imu->ubuf;
1035 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1036
1037 if (offset) {
1038 /*
1039 * Don't use iov_iter_advance() here, as it's really slow for
1040 * using the latter parts of a big fixed buffer - it iterates
1041 * over each segment manually. We can cheat a bit here, because
1042 * we know that:
1043 *
1044 * 1) it's a BVEC iter, we set it up
1045 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1046 * first and last bvec
1047 *
1048 * So just find our index, and adjust the iterator afterwards.
1049 * If the offset is within the first bvec (or the whole first
1050 * bvec, just use iov_iter_advance(). This makes it easier
1051 * since we can just skip the first segment, which may not
1052 * be PAGE_SIZE aligned.
1053 */
1054 const struct bio_vec *bvec = imu->bvec;
1055
1056 if (offset < bvec->bv_len) {
1057 /*
1058 * Note, huge pages buffers consists of one large
1059 * bvec entry and should always go this way. The other
1060 * branch doesn't expect non PAGE_SIZE'd chunks.
1061 */
1062 iter->bvec = bvec;
1063 iter->count -= offset;
1064 iter->iov_offset = offset;
1065 } else {
1066 unsigned long seg_skip;
1067
1068 /* skip first vec */
1069 offset -= bvec->bv_len;
1070 seg_skip = 1 + (offset >> PAGE_SHIFT);
1071
1072 iter->bvec = bvec + seg_skip;
1073 iter->nr_segs -= seg_skip;
1074 iter->count -= bvec->bv_len + offset;
1075 iter->iov_offset = offset & ~PAGE_MASK;
1076 }
1077 }
1078
1079 return 0;
1080 }
1081
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