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 /* copy_to_iter: required operation for fs-dax direct-i/o */
24 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
25 struct iov_iter *);
26};
27
28extern struct attribute_group dax_attribute_group;
29
30#if IS_ENABLED(CONFIG_DAX)
31struct dax_device *dax_get_by_host(const char *host);
32struct dax_device *alloc_dax(void *private, const char *host,
33 const struct dax_operations *ops);
34void put_dax(struct dax_device *dax_dev);
35void kill_dax(struct dax_device *dax_dev);
36void dax_write_cache(struct dax_device *dax_dev, bool wc);
37bool dax_write_cache_enabled(struct dax_device *dax_dev);
38#else
39static inline struct dax_device *dax_get_by_host(const char *host)
40{
41 return NULL;
42}
43static inline struct dax_device *alloc_dax(void *private, const char *host,
44 const struct dax_operations *ops)
45{
46 /*
47 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
48 * NULL is an error or expected.
49 */
50 return NULL;
51}
52static inline void put_dax(struct dax_device *dax_dev)
53{
54}
55static inline void kill_dax(struct dax_device *dax_dev)
56{
57}
58static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
59{
60}
61static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
62{
63 return false;
64}
65#endif
66
67struct writeback_control;
68int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
69#if IS_ENABLED(CONFIG_FS_DAX)
70bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
71static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
72{
73 return __bdev_dax_supported(bdev, blocksize);
74}
75
76static inline struct dax_device *fs_dax_get_by_host(const char *host)
77{
78 return dax_get_by_host(host);
79}
80
81static inline void fs_put_dax(struct dax_device *dax_dev)
82{
83 put_dax(dax_dev);
84}
85
86struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
87int dax_writeback_mapping_range(struct address_space *mapping,
88 struct block_device *bdev, struct writeback_control *wbc);
89
90struct page *dax_layout_busy_page(struct address_space *mapping);
91bool dax_lock_mapping_entry(struct page *page);
92void dax_unlock_mapping_entry(struct page *page);
93#else
94static inline bool bdev_dax_supported(struct block_device *bdev,
95 int blocksize)
96{
97 return false;
98}
99
100static inline struct dax_device *fs_dax_get_by_host(const char *host)
101{
102 return NULL;
103}
104
105static inline void fs_put_dax(struct dax_device *dax_dev)
106{
107}
108
109static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
110{
111 return NULL;
112}
113
114static inline struct page *dax_layout_busy_page(struct address_space *mapping)
115{
116 return NULL;
117}
118
119static inline int dax_writeback_mapping_range(struct address_space *mapping,
120 struct block_device *bdev, struct writeback_control *wbc)
121{
122 return -EOPNOTSUPP;
123}
124
125static inline bool dax_lock_mapping_entry(struct page *page)
126{
127 if (IS_DAX(page->mapping->host))
128 return true;
129 return false;
130}
131
132static inline void dax_unlock_mapping_entry(struct page *page)
133{
134}
135#endif
136
137int dax_read_lock(void);
138void dax_read_unlock(int id);
139bool dax_alive(struct dax_device *dax_dev);
140void *dax_get_private(struct dax_device *dax_dev);
141long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
142 void **kaddr, pfn_t *pfn);
143size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
144 size_t bytes, struct iov_iter *i);
145size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
146 size_t bytes, struct iov_iter *i);
147void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
148
149ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
150 const struct iomap_ops *ops);
151vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
152 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
153vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
154 enum page_entry_size pe_size, pfn_t pfn);
155int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
156int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
157 pgoff_t index);
158
159#ifdef CONFIG_FS_DAX
160int __dax_zero_page_range(struct block_device *bdev,
161 struct dax_device *dax_dev, sector_t sector,
162 unsigned int offset, unsigned int length);
163#else
164static inline int __dax_zero_page_range(struct block_device *bdev,
165 struct dax_device *dax_dev, sector_t sector,
166 unsigned int offset, unsigned int length)
167{
168 return -ENXIO;
169}
170#endif
171
172static inline bool dax_mapping(struct address_space *mapping)
173{
174 return mapping->host && IS_DAX(mapping->host);
175}
176
177#endif