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;
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 /* copy_from_iter: required operation for fs-dax direct-i/o */
20 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
21 struct iov_iter *);
22 /* flush: optional driver-specific cache management after writes */
23 void (*flush)(struct dax_device *, pgoff_t, void *, size_t);
24};
25
26extern struct attribute_group dax_attribute_group;
27
28#if IS_ENABLED(CONFIG_DAX)
29struct dax_device *dax_get_by_host(const char *host);
30void put_dax(struct dax_device *dax_dev);
31#else
32static inline struct dax_device *dax_get_by_host(const char *host)
33{
34 return NULL;
35}
36
37static inline void put_dax(struct dax_device *dax_dev)
38{
39}
40#endif
41
42int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
43#if IS_ENABLED(CONFIG_FS_DAX)
44int __bdev_dax_supported(struct super_block *sb, int blocksize);
45static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
46{
47 return __bdev_dax_supported(sb, blocksize);
48}
49
50static inline struct dax_device *fs_dax_get_by_host(const char *host)
51{
52 return dax_get_by_host(host);
53}
54
55static inline void fs_put_dax(struct dax_device *dax_dev)
56{
57 put_dax(dax_dev);
58}
59
60#else
61static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
62{
63 return -EOPNOTSUPP;
64}
65
66static inline struct dax_device *fs_dax_get_by_host(const char *host)
67{
68 return NULL;
69}
70
71static inline void fs_put_dax(struct dax_device *dax_dev)
72{
73}
74#endif
75
76int dax_read_lock(void);
77void dax_read_unlock(int id);
78struct dax_device *alloc_dax(void *private, const char *host,
79 const struct dax_operations *ops);
80bool dax_alive(struct dax_device *dax_dev);
81void kill_dax(struct dax_device *dax_dev);
82void *dax_get_private(struct dax_device *dax_dev);
83long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
84 void **kaddr, pfn_t *pfn);
85size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
86 size_t bytes, struct iov_iter *i);
87void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
88 size_t size);
89void dax_write_cache(struct dax_device *dax_dev, bool wc);
90
91/*
92 * We use lowest available bit in exceptional entry for locking, one bit for
93 * the entry size (PMD) and two more to tell us if the entry is a huge zero
94 * page (HZP) or an empty entry that is just used for locking. In total four
95 * special bits.
96 *
97 * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and
98 * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
99 * block allocation.
100 */
101#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4)
102#define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT)
103#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1))
104#define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
105#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
106
107static inline unsigned long dax_radix_sector(void *entry)
108{
109 return (unsigned long)entry >> RADIX_DAX_SHIFT;
110}
111
112static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
113{
114 return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
115 ((unsigned long)sector << RADIX_DAX_SHIFT) |
116 RADIX_DAX_ENTRY_LOCK);
117}
118
119ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
120 const struct iomap_ops *ops);
121int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
122 const struct iomap_ops *ops);
123int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
124int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
125 pgoff_t index);
126void dax_wake_mapping_entry_waiter(struct address_space *mapping,
127 pgoff_t index, void *entry, bool wake_all);
128
129#ifdef CONFIG_FS_DAX
130int __dax_zero_page_range(struct block_device *bdev,
131 struct dax_device *dax_dev, sector_t sector,
132 unsigned int offset, unsigned int length);
133#else
134static inline int __dax_zero_page_range(struct block_device *bdev,
135 struct dax_device *dax_dev, sector_t sector,
136 unsigned int offset, unsigned int length)
137{
138 return -ENXIO;
139}
140#endif
141
142#ifdef CONFIG_FS_DAX_PMD
143static inline unsigned int dax_radix_order(void *entry)
144{
145 if ((unsigned long)entry & RADIX_DAX_PMD)
146 return PMD_SHIFT - PAGE_SHIFT;
147 return 0;
148}
149#else
150static inline unsigned int dax_radix_order(void *entry)
151{
152 return 0;
153}
154#endif
155int dax_pfn_mkwrite(struct vm_fault *vmf);
156
157static inline bool dax_mapping(struct address_space *mapping)
158{
159 return mapping->host && IS_DAX(mapping->host);
160}
161
162struct writeback_control;
163int dax_writeback_mapping_range(struct address_space *mapping,
164 struct block_device *bdev, struct writeback_control *wbc);
165#endif