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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 **, unsigned long *);
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(vm_flags_t vm_flags,
69 const struct inode *inode,
70 struct dax_device *dax_dev)
71{
72 if (!(vm_flags & VM_SYNC))
73 return true;
74 if (!IS_DAX(inode))
75 return false;
76 return dax_synchronous(dax_dev);
77}
78#else
79static inline void *dax_holder(struct dax_device *dax_dev)
80{
81 return NULL;
82}
83static inline struct dax_device *alloc_dax(void *private,
84 const struct dax_operations *ops)
85{
86 return ERR_PTR(-EOPNOTSUPP);
87}
88static inline void put_dax(struct dax_device *dax_dev)
89{
90}
91static inline void kill_dax(struct dax_device *dax_dev)
92{
93}
94static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
95{
96}
97static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
98{
99 return false;
100}
101static inline bool dax_synchronous(struct dax_device *dax_dev)
102{
103 return true;
104}
105static inline void set_dax_nocache(struct dax_device *dax_dev)
106{
107}
108static inline void set_dax_nomc(struct dax_device *dax_dev)
109{
110}
111static inline void set_dax_synchronous(struct dax_device *dax_dev)
112{
113}
114static inline bool daxdev_mapping_supported(vm_flags_t vm_flags,
115 const struct inode *inode,
116 struct dax_device *dax_dev)
117{
118 return !(vm_flags & VM_SYNC);
119}
120static inline size_t dax_recovery_write(struct dax_device *dax_dev,
121 pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
122{
123 return 0;
124}
125#endif
126
127struct writeback_control;
128#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
129int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
130void dax_remove_host(struct gendisk *disk);
131struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
132 void *holder, const struct dax_holder_operations *ops);
133void fs_put_dax(struct dax_device *dax_dev, void *holder);
134#else
135static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
136{
137 return 0;
138}
139static inline void dax_remove_host(struct gendisk *disk)
140{
141}
142static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
143 u64 *start_off, void *holder,
144 const struct dax_holder_operations *ops)
145{
146 return NULL;
147}
148static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
149{
150}
151#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
152
153#if IS_ENABLED(CONFIG_FS_DAX)
154int dax_writeback_mapping_range(struct address_space *mapping,
155 struct dax_device *dax_dev, struct writeback_control *wbc);
156
157struct page *dax_layout_busy_page(struct address_space *mapping);
158struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
159dax_entry_t dax_lock_folio(struct folio *folio);
160void dax_unlock_folio(struct folio *folio, dax_entry_t cookie);
161dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
162 unsigned long index, struct page **page);
163void dax_unlock_mapping_entry(struct address_space *mapping,
164 unsigned long index, dax_entry_t cookie);
165#else
166static inline struct page *dax_layout_busy_page(struct address_space *mapping)
167{
168 return NULL;
169}
170
171static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
172{
173 return NULL;
174}
175
176static inline int dax_writeback_mapping_range(struct address_space *mapping,
177 struct dax_device *dax_dev, struct writeback_control *wbc)
178{
179 return -EOPNOTSUPP;
180}
181
182static inline dax_entry_t dax_lock_folio(struct folio *folio)
183{
184 if (IS_DAX(folio->mapping->host))
185 return ~0UL;
186 return 0;
187}
188
189static inline void dax_unlock_folio(struct folio *folio, dax_entry_t cookie)
190{
191}
192
193static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
194 unsigned long index, struct page **page)
195{
196 return 0;
197}
198
199static inline void dax_unlock_mapping_entry(struct address_space *mapping,
200 unsigned long index, dax_entry_t cookie)
201{
202}
203#endif
204
205int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
206 const struct iomap_ops *ops);
207int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
208 const struct iomap_ops *ops);
209int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
210 const struct iomap_ops *ops);
211
212static inline bool dax_page_is_idle(struct page *page)
213{
214 return page && page_ref_count(page) == 0;
215}
216
217#if IS_ENABLED(CONFIG_DAX)
218int dax_read_lock(void);
219void dax_read_unlock(int id);
220#else
221static inline int dax_read_lock(void)
222{
223 return 0;
224}
225
226static inline void dax_read_unlock(int id)
227{
228}
229#endif /* CONFIG_DAX */
230
231#if !IS_ENABLED(CONFIG_FS_DAX)
232static inline int __must_check dax_break_layout(struct inode *inode,
233 loff_t start, loff_t end, void (cb)(struct inode *))
234{
235 return 0;
236}
237
238static inline void dax_break_layout_final(struct inode *inode)
239{
240}
241#endif
242
243bool dax_alive(struct dax_device *dax_dev);
244void *dax_get_private(struct dax_device *dax_dev);
245long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
246 enum dax_access_mode mode, void **kaddr, unsigned long *pfn);
247size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
248 size_t bytes, struct iov_iter *i);
249size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
250 size_t bytes, struct iov_iter *i);
251int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
252 size_t nr_pages);
253int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
254 int mf_flags);
255void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
256
257ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
258 const struct iomap_ops *ops);
259vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
260 unsigned long *pfnp, int *errp,
261 const struct iomap_ops *ops);
262vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
263 unsigned int order, unsigned long pfn);
264int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
265void dax_delete_mapping_range(struct address_space *mapping,
266 loff_t start, loff_t end);
267int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
268 pgoff_t index);
269int __must_check dax_break_layout(struct inode *inode, loff_t start,
270 loff_t end, void (cb)(struct inode *));
271static inline int __must_check dax_break_layout_inode(struct inode *inode,
272 void (cb)(struct inode *))
273{
274 return dax_break_layout(inode, start: 0, LLONG_MAX, cb);
275}
276void dax_break_layout_final(struct inode *inode);
277int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
278 struct inode *dest, loff_t destoff,
279 loff_t len, bool *is_same,
280 const struct iomap_ops *ops);
281int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
282 struct file *file_out, loff_t pos_out,
283 loff_t *len, unsigned int remap_flags,
284 const struct iomap_ops *ops);
285static inline bool dax_mapping(struct address_space *mapping)
286{
287 return mapping->host && IS_DAX(mapping->host);
288}
289
290/*
291 * Due to dax's memory and block duo personalities, hwpoison reporting
292 * takes into consideration which personality is presently visible.
293 * When dax acts like a block device, such as in block IO, an encounter of
294 * dax hwpoison is reported as -EIO.
295 * When dax acts like memory, such as in page fault, a detection of hwpoison
296 * is reported as -EHWPOISON which leads to VM_FAULT_HWPOISON.
297 */
298static inline int dax_mem2blk_err(int err)
299{
300 return (err == -EHWPOISON) ? -EIO : err;
301}
302
303#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
304void hmem_register_resource(int target_nid, struct resource *r);
305#else
306static inline void hmem_register_resource(int target_nid, struct resource *r)
307{
308}
309#endif
310
311typedef int (*walk_hmem_fn)(struct device *dev, int target_nid,
312 const struct resource *res);
313int walk_hmem_resources(struct device *dev, walk_hmem_fn fn);
314#endif
315

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