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
);