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 dax_read_lock(void);
22 void dax_read_unlock(int id);
23 struct dax_device *dax_get_by_host(const char *host);
24 struct dax_device *alloc_dax(void *private, const char *host,
25 const struct dax_operations *ops);
26 void put_dax(struct dax_device *dax_dev);
27 bool dax_alive(struct dax_device *dax_dev);
28 void kill_dax(struct dax_device *dax_dev);
29 void *dax_get_private(struct dax_device *dax_dev);
30 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
31 void **kaddr, pfn_t *pfn);
34 * We use lowest available bit in exceptional entry for locking, one bit for
35 * the entry size (PMD) and two more to tell us if the entry is a huge zero
36 * page (HZP) or an empty entry that is just used for locking. In total four
39 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
40 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
43 #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
44 #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
45 #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
46 #define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
47 #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
49 static inline unsigned long dax_radix_sector(void *entry)
51 return (unsigned long)entry >> RADIX_DAX_SHIFT;
54 static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
56 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
57 ((unsigned long)sector << RADIX_DAX_SHIFT) |
58 RADIX_DAX_ENTRY_LOCK);
61 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
62 const struct iomap_ops *ops);
63 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
64 const struct iomap_ops *ops);
65 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
66 int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index);
67 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
69 void dax_wake_mapping_entry_waiter(struct address_space *mapping,
70 pgoff_t index, void *entry, bool wake_all);
73 int __dax_zero_page_range(struct block_device *bdev,
74 struct dax_device *dax_dev, sector_t sector,
75 unsigned int offset, unsigned int length);
77 static inline int __dax_zero_page_range(struct block_device *bdev,
78 struct dax_device *dax_dev, sector_t sector,
79 unsigned int offset, unsigned int length)
85 #ifdef CONFIG_FS_DAX_PMD
86 static inline unsigned int dax_radix_order(void *entry)
88 if ((unsigned long)entry & RADIX_DAX_PMD)
89 return PMD_SHIFT - PAGE_SHIFT;
93 static inline unsigned int dax_radix_order(void *entry)
98 int dax_pfn_mkwrite(struct vm_fault *vmf);
100 static inline bool vma_is_dax(struct vm_area_struct *vma)
102 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
105 static inline bool dax_mapping(struct address_space *mapping)
107 return mapping->host && IS_DAX(mapping->host);
110 struct writeback_control;
111 int dax_writeback_mapping_range(struct address_space *mapping,
112 struct block_device *bdev, struct writeback_control *wbc);