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
10 struct iomap_ops;
11 struct dax_device;
12 struct 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
28 extern struct attribute_group dax_attribute_group;
29
30 #if IS_ENABLED(CONFIG_DAX)
31 struct dax_device *dax_get_by_host(const char *host);
32 struct dax_device *alloc_dax(void *private, const char *host,
33 const struct dax_operations *ops);
34 void put_dax(struct dax_device *dax_dev);
35 void kill_dax(struct dax_device *dax_dev);
36 void dax_write_cache(struct dax_device *dax_dev, bool wc);
37 bool dax_write_cache_enabled(struct dax_device *dax_dev);
38 #else
dax_get_by_host(const char * host)39 static inline struct dax_device *dax_get_by_host(const char *host)
40 {
41 return NULL;
42 }
alloc_dax(void * private,const char * host,const struct dax_operations * ops)43 static 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 }
put_dax(struct dax_device * dax_dev)52 static inline void put_dax(struct dax_device *dax_dev)
53 {
54 }
kill_dax(struct dax_device * dax_dev)55 static inline void kill_dax(struct dax_device *dax_dev)
56 {
57 }
dax_write_cache(struct dax_device * dax_dev,bool wc)58 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
59 {
60 }
dax_write_cache_enabled(struct dax_device * dax_dev)61 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
62 {
63 return false;
64 }
65 #endif
66
67 struct writeback_control;
68 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
69 #if IS_ENABLED(CONFIG_FS_DAX)
70 bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
bdev_dax_supported(struct block_device * bdev,int blocksize)71 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
72 {
73 return __bdev_dax_supported(bdev, blocksize);
74 }
75
fs_dax_get_by_host(const char * host)76 static inline struct dax_device *fs_dax_get_by_host(const char *host)
77 {
78 return dax_get_by_host(host);
79 }
80
fs_put_dax(struct dax_device * dax_dev)81 static inline void fs_put_dax(struct dax_device *dax_dev)
82 {
83 put_dax(dax_dev);
84 }
85
86 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
87 int dax_writeback_mapping_range(struct address_space *mapping,
88 struct block_device *bdev, struct writeback_control *wbc);
89
90 struct page *dax_layout_busy_page(struct address_space *mapping);
91 bool dax_lock_mapping_entry(struct page *page);
92 void dax_unlock_mapping_entry(struct page *page);
93 #else
bdev_dax_supported(struct block_device * bdev,int blocksize)94 static inline bool bdev_dax_supported(struct block_device *bdev,
95 int blocksize)
96 {
97 return false;
98 }
99
fs_dax_get_by_host(const char * host)100 static inline struct dax_device *fs_dax_get_by_host(const char *host)
101 {
102 return NULL;
103 }
104
fs_put_dax(struct dax_device * dax_dev)105 static inline void fs_put_dax(struct dax_device *dax_dev)
106 {
107 }
108
fs_dax_get_by_bdev(struct block_device * bdev)109 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
110 {
111 return NULL;
112 }
113
dax_layout_busy_page(struct address_space * mapping)114 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
115 {
116 return NULL;
117 }
118
dax_writeback_mapping_range(struct address_space * mapping,struct block_device * bdev,struct writeback_control * wbc)119 static 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
dax_lock_mapping_entry(struct page * page)125 static 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
dax_unlock_mapping_entry(struct page * page)132 static inline void dax_unlock_mapping_entry(struct page *page)
133 {
134 }
135 #endif
136
137 int dax_read_lock(void);
138 void dax_read_unlock(int id);
139 bool dax_alive(struct dax_device *dax_dev);
140 void *dax_get_private(struct dax_device *dax_dev);
141 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
142 void **kaddr, pfn_t *pfn);
143 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
144 size_t bytes, struct iov_iter *i);
145 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
146 size_t bytes, struct iov_iter *i);
147 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
148
149 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
150 const struct iomap_ops *ops);
151 vm_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);
153 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
154 enum page_entry_size pe_size, pfn_t pfn);
155 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
156 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
157 pgoff_t index);
158
159 #ifdef CONFIG_FS_DAX
160 int __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
__dax_zero_page_range(struct block_device * bdev,struct dax_device * dax_dev,sector_t sector,unsigned int offset,unsigned int length)164 static 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
dax_mapping(struct address_space * mapping)172 static inline bool dax_mapping(struct address_space *mapping)
173 {
174 return mapping->host && IS_DAX(mapping->host);
175 }
176
177 #endif
178