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);