1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_DAX_H
3 #define _LINUX_DAX_H
4
5 #include <linux/fs.h>
6 #include <linux/mm.h>
7 #include <linux/radix-tree.h>
8
9 typedef unsigned long dax_entry_t;
10
11 struct dax_device;
12 struct gendisk;
13 struct iomap_ops;
14 struct iomap_iter;
15 struct iomap;
16
17 enum dax_access_mode {
18 DAX_ACCESS,
19 DAX_RECOVERY_WRITE,
20 };
21
22 struct dax_operations {
23 /*
24 * direct_access: translate a device-relative
25 * logical-page-offset into an absolute physical pfn. Return the
26 * number of pages available for DAX at that pfn.
27 */
28 long (*direct_access)(struct dax_device *, pgoff_t, long,
29 enum dax_access_mode, void **, pfn_t *);
30 /*
31 * Validate whether this device is usable as an fsdax backing
32 * device.
33 */
34 bool (*dax_supported)(struct dax_device *, struct block_device *, int,
35 sector_t, sector_t);
36 /* zero_page_range: required operation. Zero page range */
37 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
38 /*
39 * recovery_write: recover a poisoned range by DAX device driver
40 * capable of clearing poison.
41 */
42 size_t (*recovery_write)(struct dax_device *dax_dev, pgoff_t pgoff,
43 void *addr, size_t bytes, struct iov_iter *iter);
44 };
45
46 struct dax_holder_operations {
47 /*
48 * notify_failure - notify memory failure into inner holder device
49 * @dax_dev: the dax device which contains the holder
50 * @offset: offset on this dax device where memory failure occurs
51 * @len: length of this memory failure event
52 * @flags: action flags for memory failure handler
53 */
54 int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
55 u64 len, int mf_flags);
56 };
57
58 #if IS_ENABLED(CONFIG_DAX)
59 struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
60 void *dax_holder(struct dax_device *dax_dev);
61 void put_dax(struct dax_device *dax_dev);
62 void kill_dax(struct dax_device *dax_dev);
63 void dax_write_cache(struct dax_device *dax_dev, bool wc);
64 bool dax_write_cache_enabled(struct dax_device *dax_dev);
65 bool dax_synchronous(struct dax_device *dax_dev);
66 void set_dax_nocache(struct dax_device *dax_dev);
67 void set_dax_nomc(struct dax_device *dax_dev);
68 void set_dax_synchronous(struct dax_device *dax_dev);
69 size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
70 void *addr, size_t bytes, struct iov_iter *i);
71 /*
72 * Check if given mapping is supported by the file / underlying device.
73 */
74 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
75 struct dax_device *dax_dev)
76 {
77 if (!(vma->vm_flags & VM_SYNC))
78 return true;
79 if (!IS_DAX(file_inode(vma->vm_file)))
80 return false;
81 return dax_synchronous(dax_dev);
82 }
83 #else
84 static inline void *dax_holder(struct dax_device *dax_dev)
85 {
86 return NULL;
87 }
88 static inline struct dax_device *alloc_dax(void *private,
89 const struct dax_operations *ops)
90 {
91 return ERR_PTR(-EOPNOTSUPP);
92 }
93 static inline void put_dax(struct dax_device *dax_dev)
94 {
95 }
96 static inline void kill_dax(struct dax_device *dax_dev)
97 {
98 }
99 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
100 {
101 }
102 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
103 {
104 return false;
105 }
106 static inline bool dax_synchronous(struct dax_device *dax_dev)
107 {
108 return true;
109 }
110 static inline void set_dax_nocache(struct dax_device *dax_dev)
111 {
112 }
113 static inline void set_dax_nomc(struct dax_device *dax_dev)
114 {
115 }
116 static inline void set_dax_synchronous(struct dax_device *dax_dev)
117 {
118 }
119 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
120 struct dax_device *dax_dev)
121 {
122 return !(vma->vm_flags & VM_SYNC);
123 }
124 static inline size_t dax_recovery_write(struct dax_device *dax_dev,
125 pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
126 {
127 return 0;
128 }
129 #endif
130
131 struct writeback_control;
132 #if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
133 int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
134 void dax_remove_host(struct gendisk *disk);
135 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
136 void *holder, const struct dax_holder_operations *ops);
137 void fs_put_dax(struct dax_device *dax_dev, void *holder);
138 #else
139 static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
140 {
141 return 0;
142 }
143 static inline void dax_remove_host(struct gendisk *disk)
144 {
145 }
146 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
147 u64 *start_off, void *holder,
148 const struct dax_holder_operations *ops)
149 {
150 return NULL;
151 }
152 static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
153 {
154 }
155 #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
156
157 #if IS_ENABLED(CONFIG_FS_DAX)
158 int dax_writeback_mapping_range(struct address_space *mapping,
159 struct dax_device *dax_dev, struct writeback_control *wbc);
160
161 struct page *dax_layout_busy_page(struct address_space *mapping);
162 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
163 dax_entry_t dax_lock_folio(struct folio *folio);
164 void dax_unlock_folio(struct folio *folio, dax_entry_t cookie);
165 dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
166 unsigned long index, struct page **page);
167 void dax_unlock_mapping_entry(struct address_space *mapping,
168 unsigned long index, dax_entry_t cookie);
169 #else
170 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
171 {
172 return NULL;
173 }
174
175 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
176 {
177 return NULL;
178 }
179
180 static inline int dax_writeback_mapping_range(struct address_space *mapping,
181 struct dax_device *dax_dev, struct writeback_control *wbc)
182 {
183 return -EOPNOTSUPP;
184 }
185
186 static inline dax_entry_t dax_lock_folio(struct folio *folio)
187 {
188 if (IS_DAX(folio->mapping->host))
189 return ~0UL;
190 return 0;
191 }
192
193 static inline void dax_unlock_folio(struct folio *folio, dax_entry_t cookie)
194 {
195 }
196
197 static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
198 unsigned long index, struct page **page)
199 {
200 return 0;
201 }
202
203 static inline void dax_unlock_mapping_entry(struct address_space *mapping,
204 unsigned long index, dax_entry_t cookie)
205 {
206 }
207 #endif
208
209 int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
210 const struct iomap_ops *ops);
211 int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
212 const struct iomap_ops *ops);
213 int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
214 const struct iomap_ops *ops);
215
216 #if IS_ENABLED(CONFIG_DAX)
217 int dax_read_lock(void);
218 void dax_read_unlock(int id);
219 #else
220 static inline int dax_read_lock(void)
221 {
222 return 0;
223 }
224
225 static inline void dax_read_unlock(int id)
226 {
227 }
228 #endif /* CONFIG_DAX */
229 bool dax_alive(struct dax_device *dax_dev);
230 void *dax_get_private(struct dax_device *dax_dev);
231 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
232 enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
233 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
234 size_t bytes, struct iov_iter *i);
235 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
236 size_t bytes, struct iov_iter *i);
237 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
238 size_t nr_pages);
239 int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
240 int mf_flags);
241 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
242
243 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
244 const struct iomap_ops *ops);
245 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
246 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
247 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
248 unsigned int order, pfn_t pfn);
249 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
250 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
251 pgoff_t index);
252 int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
253 struct inode *dest, loff_t destoff,
254 loff_t len, bool *is_same,
255 const struct iomap_ops *ops);
256 int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
257 struct file *file_out, loff_t pos_out,
258 loff_t *len, unsigned int remap_flags,
259 const struct iomap_ops *ops);
260 static inline bool dax_mapping(struct address_space *mapping)
261 {
262 return mapping->host && IS_DAX(mapping->host);
263 }
264
265 /*
266 * Due to dax's memory and block duo personalities, hwpoison reporting
267 * takes into consideration which personality is presently visible.
268 * When dax acts like a block device, such as in block IO, an encounter of
269 * dax hwpoison is reported as -EIO.
270 * When dax acts like memory, such as in page fault, a detection of hwpoison
271 * is reported as -EHWPOISON which leads to VM_FAULT_HWPOISON.
272 */
273 static inline int dax_mem2blk_err(int err)
274 {
275 return (err == -EHWPOISON) ? -EIO : err;
276 }
277
278 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES
279 void hmem_register_resource(int target_nid, struct resource *r);
280 #else
281 static inline void hmem_register_resource(int target_nid, struct resource *r)
282 {
283 }
284 #endif
285
286 typedef int (*walk_hmem_fn)(struct device *dev, int target_nid,
287 const struct resource *res);
288 int walk_hmem_resources(struct device *dev, walk_hmem_fn fn);
289 #endif
290
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