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#include <asm/pgtable.h>
9
10struct iomap_ops;
11struct dax_device;
12struct dax_operations {
13 /*
14 * direct_access: translate a device-relative
15 * logical-page-offset into an absolute physical pfn. Return the
16 * number of pages available for DAX at that pfn.
17 */
18 long (*direct_access)(struct dax_device *, pgoff_t, long,
19 void **, pfn_t *);
20 /* copy_from_iter: required operation for fs-dax direct-i/o */
21 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
22 struct iov_iter *);
23};
24
25extern struct attribute_group dax_attribute_group;
26
27#if IS_ENABLED(CONFIG_DAX)
28struct dax_device *dax_get_by_host(const char *host);
29struct dax_device *alloc_dax(void *private, const char *host,
30 const struct dax_operations *ops);
31void put_dax(struct dax_device *dax_dev);
32void kill_dax(struct dax_device *dax_dev);
33void dax_write_cache(struct dax_device *dax_dev, bool wc);
34bool dax_write_cache_enabled(struct dax_device *dax_dev);
35#else
36static inline struct dax_device *dax_get_by_host(const char *host)
37{
38 return NULL;
39}
40static inline struct dax_device *alloc_dax(void *private, const char *host,
41 const struct dax_operations *ops)
42{
43 /*
44 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
45 * NULL is an error or expected.
46 */
47 return NULL;
48}
49static inline void put_dax(struct dax_device *dax_dev)
50{
51}
52static inline void kill_dax(struct dax_device *dax_dev)
53{
54}
55static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
56{
57}
58static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
59{
60 return false;
61}
62#endif
63
64struct writeback_control;
65int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
66#if IS_ENABLED(CONFIG_FS_DAX)
67int __bdev_dax_supported(struct super_block *sb, int blocksize);
68static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
69{
70 return __bdev_dax_supported(sb, blocksize);
71}
72
73static inline struct dax_device *fs_dax_get_by_host(const char *host)
74{
75 return dax_get_by_host(host);
76}
77
78static inline void fs_put_dax(struct dax_device *dax_dev)
79{
80 put_dax(dax_dev);
81}
82
83struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
84int dax_writeback_mapping_range(struct address_space *mapping,
85 struct block_device *bdev, struct writeback_control *wbc);
86#else
87static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
88{
89 return -EOPNOTSUPP;
90}
91
92static inline struct dax_device *fs_dax_get_by_host(const char *host)
93{
94 return NULL;
95}
96
97static inline void fs_put_dax(struct dax_device *dax_dev)
98{
99}
100
101static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
102{
103 return NULL;
104}
105
106static inline int dax_writeback_mapping_range(struct address_space *mapping,
107 struct block_device *bdev, struct writeback_control *wbc)
108{
109 return -EOPNOTSUPP;
110}
111#endif
112
113int dax_read_lock(void);
114void dax_read_unlock(int id);
115bool dax_alive(struct dax_device *dax_dev);
116void *dax_get_private(struct dax_device *dax_dev);
117long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
118 void **kaddr, pfn_t *pfn);
119size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
120 size_t bytes, struct iov_iter *i);
121void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
122
123ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
124 const struct iomap_ops *ops);
125int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
126 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
127int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
128 pfn_t pfn);
129int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
130int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
131 pgoff_t index);
132
133#ifdef CONFIG_FS_DAX
134int __dax_zero_page_range(struct block_device *bdev,
135 struct dax_device *dax_dev, sector_t sector,
136 unsigned int offset, unsigned int length);
137#else
138static inline int __dax_zero_page_range(struct block_device *bdev,
139 struct dax_device *dax_dev, sector_t sector,
140 unsigned int offset, unsigned int length)
141{
142 return -ENXIO;
143}
144#endif
145
146static inline bool dax_mapping(struct address_space *mapping)
147{
148 return mapping->host && IS_DAX(mapping->host);
149}
150
151#endif