Linux kernel mirror (for testing)
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linux
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/* Flag for synchronous flush */
10#define DAXDEV_F_SYNC (1UL << 0)
11
12typedef unsigned long dax_entry_t;
13
14struct iomap_ops;
15struct iomap;
16struct dax_device;
17struct dax_operations {
18 /*
19 * direct_access: translate a device-relative
20 * logical-page-offset into an absolute physical pfn. Return the
21 * number of pages available for DAX at that pfn.
22 */
23 long (*direct_access)(struct dax_device *, pgoff_t, long,
24 void **, pfn_t *);
25 /*
26 * Validate whether this device is usable as an fsdax backing
27 * device.
28 */
29 bool (*dax_supported)(struct dax_device *, struct block_device *, int,
30 sector_t, sector_t);
31 /* copy_from_iter: required operation for fs-dax direct-i/o */
32 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
33 struct iov_iter *);
34 /* copy_to_iter: required operation for fs-dax direct-i/o */
35 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
36 struct iov_iter *);
37 /* zero_page_range: required operation. Zero page range */
38 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
39};
40
41extern struct attribute_group dax_attribute_group;
42
43#if IS_ENABLED(CONFIG_DAX)
44struct dax_device *dax_get_by_host(const char *host);
45struct dax_device *alloc_dax(void *private, const char *host,
46 const struct dax_operations *ops, unsigned long flags);
47void put_dax(struct dax_device *dax_dev);
48void kill_dax(struct dax_device *dax_dev);
49void dax_write_cache(struct dax_device *dax_dev, bool wc);
50bool dax_write_cache_enabled(struct dax_device *dax_dev);
51bool __dax_synchronous(struct dax_device *dax_dev);
52static inline bool dax_synchronous(struct dax_device *dax_dev)
53{
54 return __dax_synchronous(dax_dev);
55}
56void __set_dax_synchronous(struct dax_device *dax_dev);
57static inline void set_dax_synchronous(struct dax_device *dax_dev)
58{
59 __set_dax_synchronous(dax_dev);
60}
61bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
62 int blocksize, sector_t start, sector_t len);
63/*
64 * Check if given mapping is supported by the file / underlying device.
65 */
66static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
67 struct dax_device *dax_dev)
68{
69 if (!(vma->vm_flags & VM_SYNC))
70 return true;
71 if (!IS_DAX(file_inode(vma->vm_file)))
72 return false;
73 return dax_synchronous(dax_dev);
74}
75#else
76static inline struct dax_device *dax_get_by_host(const char *host)
77{
78 return NULL;
79}
80static inline struct dax_device *alloc_dax(void *private, const char *host,
81 const struct dax_operations *ops, unsigned long flags)
82{
83 /*
84 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
85 * NULL is an error or expected.
86 */
87 return NULL;
88}
89static inline void put_dax(struct dax_device *dax_dev)
90{
91}
92static inline void kill_dax(struct dax_device *dax_dev)
93{
94}
95static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
96{
97}
98static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
99{
100 return false;
101}
102static inline bool dax_synchronous(struct dax_device *dax_dev)
103{
104 return true;
105}
106static inline void set_dax_synchronous(struct dax_device *dax_dev)
107{
108}
109static inline bool dax_supported(struct dax_device *dax_dev,
110 struct block_device *bdev, int blocksize, sector_t start,
111 sector_t len)
112{
113 return false;
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}
120#endif
121
122struct writeback_control;
123int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
124#if IS_ENABLED(CONFIG_FS_DAX)
125bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
126static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
127{
128 return __bdev_dax_supported(bdev, blocksize);
129}
130
131bool __generic_fsdax_supported(struct dax_device *dax_dev,
132 struct block_device *bdev, int blocksize, sector_t start,
133 sector_t sectors);
134static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
135 struct block_device *bdev, int blocksize, sector_t start,
136 sector_t sectors)
137{
138 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
139 sectors);
140}
141
142static inline void fs_put_dax(struct dax_device *dax_dev)
143{
144 put_dax(dax_dev);
145}
146
147struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
148int dax_writeback_mapping_range(struct address_space *mapping,
149 struct dax_device *dax_dev, struct writeback_control *wbc);
150
151struct page *dax_layout_busy_page(struct address_space *mapping);
152dax_entry_t dax_lock_page(struct page *page);
153void dax_unlock_page(struct page *page, dax_entry_t cookie);
154#else
155static inline bool bdev_dax_supported(struct block_device *bdev,
156 int blocksize)
157{
158 return false;
159}
160
161static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
162 struct block_device *bdev, int blocksize, sector_t start,
163 sector_t sectors)
164{
165 return false;
166}
167
168static inline void fs_put_dax(struct dax_device *dax_dev)
169{
170}
171
172static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
173{
174 return NULL;
175}
176
177static inline struct page *dax_layout_busy_page(struct address_space *mapping)
178{
179 return NULL;
180}
181
182static inline int dax_writeback_mapping_range(struct address_space *mapping,
183 struct dax_device *dax_dev, struct writeback_control *wbc)
184{
185 return -EOPNOTSUPP;
186}
187
188static inline dax_entry_t dax_lock_page(struct page *page)
189{
190 if (IS_DAX(page->mapping->host))
191 return ~0UL;
192 return 0;
193}
194
195static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
196{
197}
198#endif
199
200#if IS_ENABLED(CONFIG_DAX)
201int dax_read_lock(void);
202void dax_read_unlock(int id);
203#else
204static inline int dax_read_lock(void)
205{
206 return 0;
207}
208
209static inline void dax_read_unlock(int id)
210{
211}
212#endif /* CONFIG_DAX */
213bool dax_alive(struct dax_device *dax_dev);
214void *dax_get_private(struct dax_device *dax_dev);
215long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
216 void **kaddr, pfn_t *pfn);
217size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
218 size_t bytes, struct iov_iter *i);
219size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
220 size_t bytes, struct iov_iter *i);
221int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
222 size_t nr_pages);
223void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
224
225ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
226 const struct iomap_ops *ops);
227vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
228 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
229vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
230 enum page_entry_size pe_size, pfn_t pfn);
231int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
232int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
233 pgoff_t index);
234int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size,
235 struct iomap *iomap);
236static inline bool dax_mapping(struct address_space *mapping)
237{
238 return mapping->host && IS_DAX(mapping->host);
239}
240
241#endif