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}
61/*
62 * Check if given mapping is supported by the file / underlying device.
63 */
64static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
65 struct dax_device *dax_dev)
66{
67 if (!(vma->vm_flags & VM_SYNC))
68 return true;
69 if (!IS_DAX(file_inode(vma->vm_file)))
70 return false;
71 return dax_synchronous(dax_dev);
72}
73#else
74static inline struct dax_device *dax_get_by_host(const char *host)
75{
76 return NULL;
77}
78static inline struct dax_device *alloc_dax(void *private, const char *host,
79 const struct dax_operations *ops, unsigned long flags)
80{
81 /*
82 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
83 * NULL is an error or expected.
84 */
85 return NULL;
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_synchronous(struct dax_device *dax_dev)
105{
106}
107static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
108 struct dax_device *dax_dev)
109{
110 return !(vma->vm_flags & VM_SYNC);
111}
112#endif
113
114struct writeback_control;
115int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
116#if IS_ENABLED(CONFIG_FS_DAX)
117bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
118static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
119{
120 return __bdev_dax_supported(bdev, blocksize);
121}
122
123bool __generic_fsdax_supported(struct dax_device *dax_dev,
124 struct block_device *bdev, int blocksize, sector_t start,
125 sector_t sectors);
126static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
127 struct block_device *bdev, int blocksize, sector_t start,
128 sector_t sectors)
129{
130 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
131 sectors);
132}
133
134static inline void fs_put_dax(struct dax_device *dax_dev)
135{
136 put_dax(dax_dev);
137}
138
139struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
140int dax_writeback_mapping_range(struct address_space *mapping,
141 struct dax_device *dax_dev, struct writeback_control *wbc);
142
143struct page *dax_layout_busy_page(struct address_space *mapping);
144dax_entry_t dax_lock_page(struct page *page);
145void dax_unlock_page(struct page *page, dax_entry_t cookie);
146#else
147static inline bool bdev_dax_supported(struct block_device *bdev,
148 int blocksize)
149{
150 return false;
151}
152
153static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
154 struct block_device *bdev, int blocksize, sector_t start,
155 sector_t sectors)
156{
157 return false;
158}
159
160static inline void fs_put_dax(struct dax_device *dax_dev)
161{
162}
163
164static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
165{
166 return NULL;
167}
168
169static inline struct page *dax_layout_busy_page(struct address_space *mapping)
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_page(struct page *page)
181{
182 if (IS_DAX(page->mapping->host))
183 return ~0UL;
184 return 0;
185}
186
187static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
188{
189}
190#endif
191
192int dax_read_lock(void);
193void dax_read_unlock(int id);
194bool dax_alive(struct dax_device *dax_dev);
195void *dax_get_private(struct dax_device *dax_dev);
196long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
197 void **kaddr, pfn_t *pfn);
198bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
199 int blocksize, sector_t start, sector_t len);
200size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
201 size_t bytes, struct iov_iter *i);
202size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
203 size_t bytes, struct iov_iter *i);
204int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
205 size_t nr_pages);
206void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
207
208ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
209 const struct iomap_ops *ops);
210vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
211 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
212vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
213 enum page_entry_size pe_size, pfn_t pfn);
214int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
215int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
216 pgoff_t index);
217int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size,
218 struct iomap *iomap);
219static inline bool dax_mapping(struct address_space *mapping)
220{
221 return mapping->host && IS_DAX(mapping->host);
222}
223
224#endif