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 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
22 #if IS_ENABLED(CONFIG_FS_DAX)
23 int __bdev_dax_supported(struct super_block *sb, int blocksize);
24 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
26 return __bdev_dax_supported(sb, blocksize);
29 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
35 #if IS_ENABLED(CONFIG_DAX)
36 struct dax_device *dax_get_by_host(const char *host);
37 void put_dax(struct dax_device *dax_dev);
39 static inline struct dax_device *dax_get_by_host(const char *host)
44 static inline void put_dax(struct dax_device *dax_dev)
49 int dax_read_lock(void);
50 void dax_read_unlock(int id);
51 struct dax_device *alloc_dax(void *private, const char *host,
52 const struct dax_operations *ops);
53 bool dax_alive(struct dax_device *dax_dev);
54 void kill_dax(struct dax_device *dax_dev);
55 void *dax_get_private(struct dax_device *dax_dev);
56 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
57 void **kaddr, pfn_t *pfn);
60 * We use lowest available bit in exceptional entry for locking, one bit for
61 * the entry size (PMD) and two more to tell us if the entry is a huge zero
62 * page (HZP) or an empty entry that is just used for locking. In total four
65 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
66 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
69 #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
70 #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
71 #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
72 #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
73 #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
75 static inline unsigned long dax_radix_sector(void *entry)
77 return (unsigned long)entry >> RADIX_DAX_SHIFT;
80 static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
82 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
83 ((unsigned long)sector << RADIX_DAX_SHIFT) |
84 RADIX_DAX_ENTRY_LOCK);
87 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
88 const struct iomap_ops *ops);
89 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
90 const struct iomap_ops *ops);
91 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
92 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
94 void dax_wake_mapping_entry_waiter(struct address_space *mapping,
95 pgoff_t index, void *entry, bool wake_all);
98 int __dax_zero_page_range(struct block_device *bdev,
99 struct dax_device *dax_dev, sector_t sector,
100 unsigned int offset, unsigned int length);
102 static inline int __dax_zero_page_range(struct block_device *bdev,
103 struct dax_device *dax_dev, sector_t sector,
104 unsigned int offset, unsigned int length)
110 #ifdef CONFIG_FS_DAX_PMD
111 static inline unsigned int dax_radix_order(void *entry)
113 if ((unsigned long)entry & RADIX_DAX_PMD)
114 return PMD_SHIFT - PAGE_SHIFT;
118 static inline unsigned int dax_radix_order(void *entry)
123 int dax_pfn_mkwrite(struct vm_fault *vmf);
125 static inline bool vma_is_dax(struct vm_area_struct *vma)
127 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
130 static inline bool dax_mapping(struct address_space *mapping)
132 return mapping->host && IS_DAX(mapping->host);
135 struct writeback_control;
136 int dax_writeback_mapping_range(struct address_space *mapping,
137 struct block_device *bdev, struct writeback_control *wbc);