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
9typedef unsigned long dax_entry_t;
10
11struct dax_device;
12struct gendisk;
13struct iomap_ops;
14struct iomap_iter;
15struct iomap;
16
17enum dax_access_mode {
18 DAX_ACCESS,
19 DAX_RECOVERY_WRITE,
20};
21
22struct 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 /* zero_page_range: required operation. Zero page range */
31 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
32 /*
33 * recovery_write: recover a poisoned range by DAX device driver
34 * capable of clearing poison.
35 */
36 size_t (*recovery_write)(struct dax_device *dax_dev, pgoff_t pgoff,
37 void *addr, size_t bytes, struct iov_iter *iter);
38};
39
40struct dax_holder_operations {
41 /*
42 * notify_failure - notify memory failure into inner holder device
43 * @dax_dev: the dax device which contains the holder
44 * @offset: offset on this dax device where memory failure occurs
45 * @len: length of this memory failure event
46 * @flags: action flags for memory failure handler
47 */
48 int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
49 u64 len, int mf_flags);
50};
51
52#if IS_ENABLED(CONFIG_DAX)
53struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
54void *dax_holder(struct dax_device *dax_dev);
55void put_dax(struct dax_device *dax_dev);
56void kill_dax(struct dax_device *dax_dev);
57void dax_write_cache(struct dax_device *dax_dev, bool wc);
58bool dax_write_cache_enabled(struct dax_device *dax_dev);
59bool dax_synchronous(struct dax_device *dax_dev);
60void set_dax_nocache(struct dax_device *dax_dev);
61void set_dax_nomc(struct dax_device *dax_dev);
62void set_dax_synchronous(struct dax_device *dax_dev);
63size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
64 void *addr, size_t bytes, struct iov_iter *i);
65/*
66 * Check if given mapping is supported by the file / underlying device.
67 */
68static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
69 struct dax_device *dax_dev)
70{
71 if (!(vma->vm_flags & VM_SYNC))
72 return true;
73 if (!IS_DAX(file_inode(vma->vm_file)))
74 return false;
75 return dax_synchronous(dax_dev);
76}
77#else
78static inline void *dax_holder(struct dax_device *dax_dev)
79{
80 return NULL;
81}
82static inline struct dax_device *alloc_dax(void *private,
83 const struct dax_operations *ops)
84{
85 return ERR_PTR(-EOPNOTSUPP);
86}
87static inline void put_dax(struct dax_device *dax_dev)
88{
89}
90static inline void kill_dax(struct dax_device *dax_dev)
91{
92}
93static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
94{
95}
96static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
97{
98 return false;
99}
100static inline bool dax_synchronous(struct dax_device *dax_dev)
101{
102 return true;
103}
104static inline void set_dax_nocache(struct dax_device *dax_dev)
105{
106}
107static inline void set_dax_nomc(struct dax_device *dax_dev)
108{
109}
110static inline void set_dax_synchronous(struct dax_device *dax_dev)
111{
112}
113static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
114 struct dax_device *dax_dev)
115{
116 return !(vma->vm_flags & VM_SYNC);
117}
118static inline size_t dax_recovery_write(struct dax_device *dax_dev,
119 pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
120{
121 return 0;
122}
123#endif
124
125struct writeback_control;
126#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
127int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
128void dax_remove_host(struct gendisk *disk);
129struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
130 void *holder, const struct dax_holder_operations *ops);
131void fs_put_dax(struct dax_device *dax_dev, void *holder);
132#else
133static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
134{
135 return 0;
136}
137static inline void dax_remove_host(struct gendisk *disk)
138{
139}
140static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
141 u64 *start_off, void *holder,
142 const struct dax_holder_operations *ops)
143{
144 return NULL;
145}
146static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
147{
148}
149#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
150
151#if IS_ENABLED(CONFIG_FS_DAX)
152int dax_writeback_mapping_range(struct address_space *mapping,
153 struct dax_device *dax_dev, struct writeback_control *wbc);
154
155struct page *dax_layout_busy_page(struct address_space *mapping);
156struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
157dax_entry_t dax_lock_folio(struct folio *folio);
158void dax_unlock_folio(struct folio *folio, dax_entry_t cookie);
159dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
160 unsigned long index, struct page **page);
161void dax_unlock_mapping_entry(struct address_space *mapping,
162 unsigned long index, dax_entry_t cookie);
163#else
164static inline struct page *dax_layout_busy_page(struct address_space *mapping)
165{
166 return NULL;
167}
168
169static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
170{
171 return NULL;
172}
173
174static inline int dax_writeback_mapping_range(struct address_space *mapping,
175 struct dax_device *dax_dev, struct writeback_control *wbc)
176{
177 return -EOPNOTSUPP;
178}
179
180static inline dax_entry_t dax_lock_folio(struct folio *folio)
181{
182 if (IS_DAX(folio->mapping->host))
183 return ~0UL;
184 return 0;
185}
186
187static inline void dax_unlock_folio(struct folio *folio, dax_entry_t cookie)
188{
189}
190
191static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
192 unsigned long index, struct page **page)
193{
194 return 0;
195}
196
197static inline void dax_unlock_mapping_entry(struct address_space *mapping,
198 unsigned long index, dax_entry_t cookie)
199{
200}
201#endif
202
203int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
204 const struct iomap_ops *ops);
205int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
206 const struct iomap_ops *ops);
207int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
208 const struct iomap_ops *ops);
209
210static inline bool dax_page_is_idle(struct page *page)
211{
212 return page && page_ref_count(page) == 0;
213}
214
215#if IS_ENABLED(CONFIG_DAX)
216int dax_read_lock(void);
217void dax_read_unlock(int id);
218#else
219static inline int dax_read_lock(void)
220{
221 return 0;
222}
223
224static inline void dax_read_unlock(int id)
225{
226}
227#endif /* CONFIG_DAX */
228
229#if !IS_ENABLED(CONFIG_FS_DAX)
230static inline int __must_check dax_break_layout(struct inode *inode,
231 loff_t start, loff_t end, void (cb)(struct inode *))
232{
233 return 0;
234}
235
236static inline void dax_break_layout_final(struct inode *inode)
237{
238}
239#endif
240
241bool dax_alive(struct dax_device *dax_dev);
242void *dax_get_private(struct dax_device *dax_dev);
243long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
244 enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
245size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
246 size_t bytes, struct iov_iter *i);
247size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
248 size_t bytes, struct iov_iter *i);
249int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
250 size_t nr_pages);
251int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
252 int mf_flags);
253void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
254
255ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
256 const struct iomap_ops *ops);
257vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
258 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
259vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
260 unsigned int order, pfn_t pfn);
261int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
262void dax_delete_mapping_range(struct address_space *mapping,
263 loff_t start, loff_t end);
264int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
265 pgoff_t index);
266int __must_check dax_break_layout(struct inode *inode, loff_t start,
267 loff_t end, void (cb)(struct inode *));
268static inline int __must_check dax_break_layout_inode(struct inode *inode,
269 void (cb)(struct inode *))
270{
271 return dax_break_layout(inode, start: 0, LLONG_MAX, cb);
272}
273void dax_break_layout_final(struct inode *inode);
274int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
275 struct inode *dest, loff_t destoff,
276 loff_t len, bool *is_same,
277 const struct iomap_ops *ops);
278int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
279 struct file *file_out, loff_t pos_out,
280 loff_t *len, unsigned int remap_flags,
281 const struct iomap_ops *ops);
282static inline bool dax_mapping(struct address_space *mapping)
283{
284 return mapping->host && IS_DAX(mapping->host);
285}
286
287/*
288 * Due to dax's memory and block duo personalities, hwpoison reporting
289 * takes into consideration which personality is presently visible.
290 * When dax acts like a block device, such as in block IO, an encounter of
291 * dax hwpoison is reported as -EIO.
292 * When dax acts like memory, such as in page fault, a detection of hwpoison
293 * is reported as -EHWPOISON which leads to VM_FAULT_HWPOISON.
294 */
295static inline int dax_mem2blk_err(int err)
296{
297 return (err == -EHWPOISON) ? -EIO : err;
298}
299
300#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
301void hmem_register_resource(int target_nid, struct resource *r);
302#else
303static inline void hmem_register_resource(int target_nid, struct resource *r)
304{
305}
306#endif
307
308typedef int (*walk_hmem_fn)(struct device *dev, int target_nid,
309 const struct resource *res);
310int walk_hmem_resources(struct device *dev, walk_hmem_fn fn);
311#endif
312

source code of linux/include/linux/dax.h

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