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
10typedef unsigned long dax_entry_t;
11
12struct iomap_ops;
13struct dax_device;
14struct dax_operations {
15 /*
16 * direct_access: translate a device-relative
17 * logical-page-offset into an absolute physical pfn. Return the
18 * number of pages available for DAX at that pfn.
19 */
20 long (*direct_access)(struct dax_device *, pgoff_t, long,
21 void **, pfn_t *);
22 /*
23 * Validate whether this device is usable as an fsdax backing
24 * device.
25 */
26 bool (*dax_supported)(struct dax_device *, struct block_device *, int,
27 sector_t, sector_t);
28 /* copy_from_iter: required operation for fs-dax direct-i/o */
29 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
30 struct iov_iter *);
31 /* copy_to_iter: required operation for fs-dax direct-i/o */
32 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
33 struct iov_iter *);
34};
35
36extern struct attribute_group dax_attribute_group;
37
38#if IS_ENABLED(CONFIG_DAX)
39struct dax_device *dax_get_by_host(const char *host);
40struct dax_device *alloc_dax(void *private, const char *host,
41 const struct dax_operations *ops);
42void put_dax(struct dax_device *dax_dev);
43void kill_dax(struct dax_device *dax_dev);
44void dax_write_cache(struct dax_device *dax_dev, bool wc);
45bool dax_write_cache_enabled(struct dax_device *dax_dev);
46#else
47static inline struct dax_device *dax_get_by_host(const char *host)
48{
49 return NULL;
50}
51static inline struct dax_device *alloc_dax(void *private, const char *host,
52 const struct dax_operations *ops)
53{
54 /*
55 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
56 * NULL is an error or expected.
57 */
58 return NULL;
59}
60static inline void put_dax(struct dax_device *dax_dev)
61{
62}
63static inline void kill_dax(struct dax_device *dax_dev)
64{
65}
66static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
67{
68}
69static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
70{
71 return false;
72}
73#endif
74
75struct writeback_control;
76int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
77#if IS_ENABLED(CONFIG_FS_DAX)
78bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
79static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
80{
81 return __bdev_dax_supported(bdev, blocksize);
82}
83
84bool __generic_fsdax_supported(struct dax_device *dax_dev,
85 struct block_device *bdev, int blocksize, sector_t start,
86 sector_t sectors);
87static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
88 struct block_device *bdev, int blocksize, sector_t start,
89 sector_t sectors)
90{
91 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
92 sectors);
93}
94
95static inline struct dax_device *fs_dax_get_by_host(const char *host)
96{
97 return dax_get_by_host(host);
98}
99
100static inline void fs_put_dax(struct dax_device *dax_dev)
101{
102 put_dax(dax_dev);
103}
104
105struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
106int dax_writeback_mapping_range(struct address_space *mapping,
107 struct block_device *bdev, struct writeback_control *wbc);
108
109struct page *dax_layout_busy_page(struct address_space *mapping);
110dax_entry_t dax_lock_page(struct page *page);
111void dax_unlock_page(struct page *page, dax_entry_t cookie);
112#else
113static inline bool bdev_dax_supported(struct block_device *bdev,
114 int blocksize)
115{
116 return false;
117}
118
119static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
120 struct block_device *bdev, int blocksize, sector_t start,
121 sector_t sectors)
122{
123 return false;
124}
125
126static inline struct dax_device *fs_dax_get_by_host(const char *host)
127{
128 return NULL;
129}
130
131static inline void fs_put_dax(struct dax_device *dax_dev)
132{
133}
134
135static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
136{
137 return NULL;
138}
139
140static inline struct page *dax_layout_busy_page(struct address_space *mapping)
141{
142 return NULL;
143}
144
145static inline int dax_writeback_mapping_range(struct address_space *mapping,
146 struct block_device *bdev, struct writeback_control *wbc)
147{
148 return -EOPNOTSUPP;
149}
150
151static inline dax_entry_t dax_lock_page(struct page *page)
152{
153 if (IS_DAX(page->mapping->host))
154 return ~0UL;
155 return 0;
156}
157
158static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
159{
160}
161#endif
162
163int dax_read_lock(void);
164void dax_read_unlock(int id);
165bool dax_alive(struct dax_device *dax_dev);
166void *dax_get_private(struct dax_device *dax_dev);
167long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
168 void **kaddr, pfn_t *pfn);
169bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
170 int blocksize, sector_t start, sector_t len);
171size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
172 size_t bytes, struct iov_iter *i);
173size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
174 size_t bytes, struct iov_iter *i);
175void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
176
177ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
178 const struct iomap_ops *ops);
179vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
180 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
181vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
182 enum page_entry_size pe_size, pfn_t pfn);
183int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
184int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
185 pgoff_t index);
186
187#ifdef CONFIG_FS_DAX
188int __dax_zero_page_range(struct block_device *bdev,
189 struct dax_device *dax_dev, sector_t sector,
190 unsigned int offset, unsigned int length);
191#else
192static inline int __dax_zero_page_range(struct block_device *bdev,
193 struct dax_device *dax_dev, sector_t sector,
194 unsigned int offset, unsigned int length)
195{
196 return -ENXIO;
197}
198#endif
199
200static inline bool dax_mapping(struct address_space *mapping)
201{
202 return mapping->host && IS_DAX(mapping->host);
203}
204
205#endif