6 #include <linux/radix-tree.h>
7 #include <asm/pgtable.h>
11 struct dax_operations {
13 * direct_access: translate a device-relative
14 * logical-page-offset into an absolute physical pfn. Return the
15 * number of pages available for DAX at that pfn.
17 long (*direct_access)(struct dax_device *, pgoff_t, long,
19 /* copy_from_iter: required operation for fs-dax direct-i/o */
20 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
22 /* flush: optional driver-specific cache management after writes */
23 void (*flush)(struct dax_device *, pgoff_t, void *, size_t);
26 extern struct attribute_group dax_attribute_group;
28 #if IS_ENABLED(CONFIG_DAX)
29 struct dax_device *dax_get_by_host(const char *host);
30 void put_dax(struct dax_device *dax_dev);
32 static inline struct dax_device *dax_get_by_host(const char *host)
37 static inline void put_dax(struct dax_device *dax_dev)
42 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
43 #if IS_ENABLED(CONFIG_FS_DAX)
44 int __bdev_dax_supported(struct super_block *sb, int blocksize);
45 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
47 return __bdev_dax_supported(sb, blocksize);
50 static inline struct dax_device *fs_dax_get_by_host(const char *host)
52 return dax_get_by_host(host);
55 static inline void fs_put_dax(struct dax_device *dax_dev)
61 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
66 static inline struct dax_device *fs_dax_get_by_host(const char *host)
71 static inline void fs_put_dax(struct dax_device *dax_dev)
76 int dax_read_lock(void);
77 void dax_read_unlock(int id);
78 struct dax_device *alloc_dax(void *private, const char *host,
79 const struct dax_operations *ops);
80 bool dax_alive(struct dax_device *dax_dev);
81 void kill_dax(struct dax_device *dax_dev);
82 void *dax_get_private(struct dax_device *dax_dev);
83 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
84 void **kaddr, pfn_t *pfn);
85 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
86 size_t bytes, struct iov_iter *i);
87 void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
89 void dax_write_cache(struct dax_device *dax_dev, bool wc);
92 * We use lowest available bit in exceptional entry for locking, one bit for
93 * the entry size (PMD) and two more to tell us if the entry is a huge zero
94 * page (HZP) or an empty entry that is just used for locking. In total four
97 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
98 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
101 #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
102 #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
103 #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
104 #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
105 #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
107 static inline unsigned long dax_radix_sector(void *entry)
109 return (unsigned long)entry >> RADIX_DAX_SHIFT;
112 static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
114 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
115 ((unsigned long)sector << RADIX_DAX_SHIFT) |
116 RADIX_DAX_ENTRY_LOCK);
119 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
120 const struct iomap_ops *ops);
121 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
122 const struct iomap_ops *ops);
123 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
124 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
126 void dax_wake_mapping_entry_waiter(struct address_space *mapping,
127 pgoff_t index, void *entry, bool wake_all);
130 int __dax_zero_page_range(struct block_device *bdev,
131 struct dax_device *dax_dev, sector_t sector,
132 unsigned int offset, unsigned int length);
134 static inline int __dax_zero_page_range(struct block_device *bdev,
135 struct dax_device *dax_dev, sector_t sector,
136 unsigned int offset, unsigned int length)
142 #ifdef CONFIG_FS_DAX_PMD
143 static inline unsigned int dax_radix_order(void *entry)
145 if ((unsigned long)entry & RADIX_DAX_PMD)
146 return PMD_SHIFT - PAGE_SHIFT;
150 static inline unsigned int dax_radix_order(void *entry)
155 int dax_pfn_mkwrite(struct vm_fault *vmf);
157 static inline bool dax_mapping(struct address_space *mapping)
159 return mapping->host && IS_DAX(mapping->host);
162 struct writeback_control;
163 int dax_writeback_mapping_range(struct address_space *mapping,
164 struct block_device *bdev, struct writeback_control *wbc);