Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1#ifndef _LINUX_DAX_H
2#define _LINUX_DAX_H
3
4#include <linux/fs.h>
5#include <linux/mm.h>
6#include <linux/radix-tree.h>
7#include <asm/pgtable.h>
8
9struct iomap_ops;
10
11/*
12 * We use lowest available bit in exceptional entry for locking, one bit for
13 * the entry size (PMD) and two more to tell us if the entry is a huge zero
14 * page (HZP) or an empty entry that is just used for locking. In total four
15 * special bits.
16 *
17 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
18 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
19 * block allocation.
20 */
21#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
22#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
23#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
24#define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
25#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
26
27static inline unsigned long dax_radix_sector(void *entry)
28{
29 return (unsigned long)entry >> RADIX_DAX_SHIFT;
30}
31
32static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
33{
34 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
35 ((unsigned long)sector << RADIX_DAX_SHIFT) |
36 RADIX_DAX_ENTRY_LOCK);
37}
38
39ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
40 struct iomap_ops *ops);
41int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
42 struct iomap_ops *ops);
43int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
44void dax_wake_mapping_entry_waiter(struct address_space *mapping,
45 pgoff_t index, void *entry, bool wake_all);
46
47#ifdef CONFIG_FS_DAX
48struct page *read_dax_sector(struct block_device *bdev, sector_t n);
49int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
50 unsigned int offset, unsigned int length);
51#else
52static inline struct page *read_dax_sector(struct block_device *bdev,
53 sector_t n)
54{
55 return ERR_PTR(-ENXIO);
56}
57static inline int __dax_zero_page_range(struct block_device *bdev,
58 sector_t sector, unsigned int offset, unsigned int length)
59{
60 return -ENXIO;
61}
62#endif
63
64#ifdef CONFIG_FS_DAX_PMD
65static inline unsigned int dax_radix_order(void *entry)
66{
67 if ((unsigned long)entry & RADIX_DAX_PMD)
68 return PMD_SHIFT - PAGE_SHIFT;
69 return 0;
70}
71int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
72 pmd_t *pmd, unsigned int flags, struct iomap_ops *ops);
73#else
74static inline unsigned int dax_radix_order(void *entry)
75{
76 return 0;
77}
78static inline int dax_iomap_pmd_fault(struct vm_area_struct *vma,
79 unsigned long address, pmd_t *pmd, unsigned int flags,
80 struct iomap_ops *ops)
81{
82 return VM_FAULT_FALLBACK;
83}
84#endif
85int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
86
87static inline bool vma_is_dax(struct vm_area_struct *vma)
88{
89 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
90}
91
92static inline bool dax_mapping(struct address_space *mapping)
93{
94 return mapping->host && IS_DAX(mapping->host);
95}
96
97struct writeback_control;
98int dax_writeback_mapping_range(struct address_space *mapping,
99 struct block_device *bdev, struct writeback_control *wbc);
100#endif