Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
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;
10struct dax_device;
11struct dax_operations {
12 /*
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.
16 */
17 long (*direct_access)(struct dax_device *, pgoff_t, long,
18 void **, pfn_t *);
19};
20
21#if IS_ENABLED(CONFIG_DAX)
22struct dax_device *dax_get_by_host(const char *host);
23void put_dax(struct dax_device *dax_dev);
24#else
25static inline struct dax_device *dax_get_by_host(const char *host)
26{
27 return NULL;
28}
29
30static inline void put_dax(struct dax_device *dax_dev)
31{
32}
33#endif
34
35int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
36#if IS_ENABLED(CONFIG_FS_DAX)
37int __bdev_dax_supported(struct super_block *sb, int blocksize);
38static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
39{
40 return __bdev_dax_supported(sb, blocksize);
41}
42
43static inline struct dax_device *fs_dax_get_by_host(const char *host)
44{
45 return dax_get_by_host(host);
46}
47
48static inline void fs_put_dax(struct dax_device *dax_dev)
49{
50 put_dax(dax_dev);
51}
52
53#else
54static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
55{
56 return -EOPNOTSUPP;
57}
58
59static inline struct dax_device *fs_dax_get_by_host(const char *host)
60{
61 return NULL;
62}
63
64static inline void fs_put_dax(struct dax_device *dax_dev)
65{
66}
67#endif
68
69int dax_read_lock(void);
70void dax_read_unlock(int id);
71struct dax_device *alloc_dax(void *private, const char *host,
72 const struct dax_operations *ops);
73bool dax_alive(struct dax_device *dax_dev);
74void kill_dax(struct dax_device *dax_dev);
75void *dax_get_private(struct dax_device *dax_dev);
76long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
77 void **kaddr, pfn_t *pfn);
78
79/*
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
83 * special bits.
84 *
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
87 * block allocation.
88 */
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))
94
95static inline unsigned long dax_radix_sector(void *entry)
96{
97 return (unsigned long)entry >> RADIX_DAX_SHIFT;
98}
99
100static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
101{
102 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
103 ((unsigned long)sector << RADIX_DAX_SHIFT) |
104 RADIX_DAX_ENTRY_LOCK);
105}
106
107ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
108 const struct iomap_ops *ops);
109int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
110 const struct iomap_ops *ops);
111int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
112int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
113 pgoff_t index);
114void dax_wake_mapping_entry_waiter(struct address_space *mapping,
115 pgoff_t index, void *entry, bool wake_all);
116
117#ifdef CONFIG_FS_DAX
118int __dax_zero_page_range(struct block_device *bdev,
119 struct dax_device *dax_dev, sector_t sector,
120 unsigned int offset, unsigned int length);
121#else
122static 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)
125{
126 return -ENXIO;
127}
128#endif
129
130#ifdef CONFIG_FS_DAX_PMD
131static inline unsigned int dax_radix_order(void *entry)
132{
133 if ((unsigned long)entry & RADIX_DAX_PMD)
134 return PMD_SHIFT - PAGE_SHIFT;
135 return 0;
136}
137#else
138static inline unsigned int dax_radix_order(void *entry)
139{
140 return 0;
141}
142#endif
143int dax_pfn_mkwrite(struct vm_fault *vmf);
144
145static inline bool vma_is_dax(struct vm_area_struct *vma)
146{
147 return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
148}
149
150static inline bool dax_mapping(struct address_space *mapping)
151{
152 return mapping->host && IS_DAX(mapping->host);
153}
154
155struct writeback_control;
156int dax_writeback_mapping_range(struct address_space *mapping,
157 struct block_device *bdev, struct writeback_control *wbc);
158#endif