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