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,
21 #if IS_ENABLED(CONFIG_DAX)
22 struct dax_device
*dax_get_by_host(const char *host
);
23 void put_dax(struct dax_device
*dax_dev
);
25 static inline struct dax_device
*dax_get_by_host(const char *host
)
30 static inline void put_dax(struct dax_device
*dax_dev
)
35 int bdev_dax_pgoff(struct block_device
*, sector_t
, size_t, pgoff_t
*pgoff
);
36 #if IS_ENABLED(CONFIG_FS_DAX)
37 int __bdev_dax_supported(struct super_block
*sb
, int blocksize
);
38 static inline int bdev_dax_supported(struct super_block
*sb
, int blocksize
)
40 return __bdev_dax_supported(sb
, blocksize
);
43 static inline struct dax_device
*fs_dax_get_by_host(const char *host
)
45 return dax_get_by_host(host
);
48 static inline void fs_put_dax(struct dax_device
*dax_dev
)
54 static inline int bdev_dax_supported(struct super_block
*sb
, int blocksize
)
59 static inline struct dax_device
*fs_dax_get_by_host(const char *host
)
64 static inline void fs_put_dax(struct dax_device
*dax_dev
)
69 int dax_read_lock(void);
70 void dax_read_unlock(int id
);
71 struct dax_device
*alloc_dax(void *private, const char *host
,
72 const struct dax_operations
*ops
);
73 bool dax_alive(struct dax_device
*dax_dev
);
74 void kill_dax(struct dax_device
*dax_dev
);
75 void *dax_get_private(struct dax_device
*dax_dev
);
76 long dax_direct_access(struct dax_device
*dax_dev
, pgoff_t pgoff
, long nr_pages
,
77 void **kaddr
, pfn_t
*pfn
);
80 * We use lowest available bit in exceptional entry for locking, one bit for
81 * the entry size (PMD) and two more to tell us if the entry is a huge zero
82 * page (HZP) or an empty entry that is just used for locking. In total four
85 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
86 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
89 #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
90 #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
91 #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
92 #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
93 #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
95 static inline unsigned long dax_radix_sector(void *entry
)
97 return (unsigned long)entry
>> RADIX_DAX_SHIFT
;
100 static inline void *dax_radix_locked_entry(sector_t sector
, unsigned long flags
)
102 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY
| flags
|
103 ((unsigned long)sector
<< RADIX_DAX_SHIFT
) |
104 RADIX_DAX_ENTRY_LOCK
);
107 ssize_t
dax_iomap_rw(struct kiocb
*iocb
, struct iov_iter
*iter
,
108 const struct iomap_ops
*ops
);
109 int dax_iomap_fault(struct vm_fault
*vmf
, enum page_entry_size pe_size
,
110 const struct iomap_ops
*ops
);
111 int dax_delete_mapping_entry(struct address_space
*mapping
, pgoff_t index
);
112 int dax_invalidate_mapping_entry_sync(struct address_space
*mapping
,
114 void dax_wake_mapping_entry_waiter(struct address_space
*mapping
,
115 pgoff_t index
, void *entry
, bool wake_all
);
118 int __dax_zero_page_range(struct block_device
*bdev
,
119 struct dax_device
*dax_dev
, sector_t sector
,
120 unsigned int offset
, unsigned int length
);
122 static inline int __dax_zero_page_range(struct block_device
*bdev
,
123 struct dax_device
*dax_dev
, sector_t sector
,
124 unsigned int offset
, unsigned int length
)
130 #ifdef CONFIG_FS_DAX_PMD
131 static inline unsigned int dax_radix_order(void *entry
)
133 if ((unsigned long)entry
& RADIX_DAX_PMD
)
134 return PMD_SHIFT
- PAGE_SHIFT
;
138 static inline unsigned int dax_radix_order(void *entry
)
143 int dax_pfn_mkwrite(struct vm_fault
*vmf
);
145 static inline bool vma_is_dax(struct vm_area_struct
*vma
)
147 return vma
->vm_file
&& IS_DAX(vma
->vm_file
->f_mapping
->host
);
150 static inline bool dax_mapping(struct address_space
*mapping
)
152 return mapping
->host
&& IS_DAX(mapping
->host
);
155 struct writeback_control
;
156 int dax_writeback_mapping_range(struct address_space
*mapping
,
157 struct block_device
*bdev
, struct writeback_control
*wbc
);