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 /*
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
46struct 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)
59struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
60void *dax_holder(struct dax_device *dax_dev);
61void put_dax(struct dax_device *dax_dev);
62void kill_dax(struct dax_device *dax_dev);
63void dax_write_cache(struct dax_device *dax_dev, bool wc);
64bool dax_write_cache_enabled(struct dax_device *dax_dev);
65bool dax_synchronous(struct dax_device *dax_dev);
66void set_dax_synchronous(struct dax_device *dax_dev);
67size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
68 void *addr, size_t bytes, struct iov_iter *i);
69/*
70 * Check if given mapping is supported by the file / underlying device.
71 */
72static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
73 struct dax_device *dax_dev)
74{
75 if (!(vma->vm_flags & VM_SYNC))
76 return true;
77 if (!IS_DAX(file_inode(vma->vm_file)))
78 return false;
79 return dax_synchronous(dax_dev);
80}
81#else
82static inline void *dax_holder(struct dax_device *dax_dev)
83{
84 return NULL;
85}
86static inline struct dax_device *alloc_dax(void *private,
87 const struct dax_operations *ops)
88{
89 /*
90 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
91 * NULL is an error or expected.
92 */
93 return NULL;
94}
95static inline void put_dax(struct dax_device *dax_dev)
96{
97}
98static inline void kill_dax(struct dax_device *dax_dev)
99{
100}
101static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
102{
103}
104static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
105{
106 return false;
107}
108static inline bool dax_synchronous(struct dax_device *dax_dev)
109{
110 return true;
111}
112static inline void set_dax_synchronous(struct dax_device *dax_dev)
113{
114}
115static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
116 struct dax_device *dax_dev)
117{
118 return !(vma->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
127void set_dax_nocache(struct dax_device *dax_dev);
128void set_dax_nomc(struct dax_device *dax_dev);
129
130struct writeback_control;
131#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
132int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
133void dax_remove_host(struct gendisk *disk);
134struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
135 void *holder, const struct dax_holder_operations *ops);
136void fs_put_dax(struct dax_device *dax_dev, void *holder);
137#else
138static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
139{
140 return 0;
141}
142static inline void dax_remove_host(struct gendisk *disk)
143{
144}
145static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
146 u64 *start_off, void *holder,
147 const struct dax_holder_operations *ops)
148{
149 return NULL;
150}
151static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
152{
153}
154#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
155
156#if IS_ENABLED(CONFIG_FS_DAX)
157int dax_writeback_mapping_range(struct address_space *mapping,
158 struct dax_device *dax_dev, struct writeback_control *wbc);
159
160struct page *dax_layout_busy_page(struct address_space *mapping);
161struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
162dax_entry_t dax_lock_page(struct page *page);
163void dax_unlock_page(struct page *page, dax_entry_t cookie);
164dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
165 unsigned long index, struct page **page);
166void dax_unlock_mapping_entry(struct address_space *mapping,
167 unsigned long index, dax_entry_t cookie);
168#else
169static inline struct page *dax_layout_busy_page(struct address_space *mapping)
170{
171 return NULL;
172}
173
174static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
175{
176 return NULL;
177}
178
179static inline int dax_writeback_mapping_range(struct address_space *mapping,
180 struct dax_device *dax_dev, struct writeback_control *wbc)
181{
182 return -EOPNOTSUPP;
183}
184
185static inline dax_entry_t dax_lock_page(struct page *page)
186{
187 if (IS_DAX(page->mapping->host))
188 return ~0UL;
189 return 0;
190}
191
192static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
193{
194}
195
196static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
197 unsigned long index, struct page **page)
198{
199 return 0;
200}
201
202static inline void dax_unlock_mapping_entry(struct address_space *mapping,
203 unsigned long index, dax_entry_t cookie)
204{
205}
206#endif
207
208int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
209 const struct iomap_ops *ops);
210int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
211 const struct iomap_ops *ops);
212
213#if IS_ENABLED(CONFIG_DAX)
214int dax_read_lock(void);
215void dax_read_unlock(int id);
216#else
217static inline int dax_read_lock(void)
218{
219 return 0;
220}
221
222static inline void dax_read_unlock(int id)
223{
224}
225#endif /* CONFIG_DAX */
226bool dax_alive(struct dax_device *dax_dev);
227void *dax_get_private(struct dax_device *dax_dev);
228long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
229 enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
230size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
231 size_t bytes, struct iov_iter *i);
232size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
233 size_t bytes, struct iov_iter *i);
234int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
235 size_t nr_pages);
236int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
237 int mf_flags);
238void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
239
240ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
241 const struct iomap_ops *ops);
242vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
243 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
244vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
245 enum page_entry_size pe_size, pfn_t pfn);
246int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
247int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
248 pgoff_t index);
249int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
250 struct inode *dest, loff_t destoff,
251 loff_t len, bool *is_same,
252 const struct iomap_ops *ops);
253int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
254 struct file *file_out, loff_t pos_out,
255 loff_t *len, unsigned int remap_flags,
256 const struct iomap_ops *ops);
257static inline bool dax_mapping(struct address_space *mapping)
258{
259 return mapping->host && IS_DAX(mapping->host);
260}
261
262#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
263void hmem_register_device(int target_nid, struct resource *r);
264#else
265static inline void hmem_register_device(int target_nid, struct resource *r)
266{
267}
268#endif
269
270#endif
271

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