1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_DAX_H
3#define _LINUX_DAX_H
4
5#include <linux/fs.h>
6#include <linux/mm.h>
7#include <linux/radix-tree.h>
8#include <asm/pgtable.h>
9
10typedef unsigned long dax_entry_t;
11
12struct iomap_ops;
13struct dax_device;
14struct dax_operations {
15 /*
16 * direct_access: translate a device-relative
17 * logical-page-offset into an absolute physical pfn. Return the
18 * number of pages available for DAX at that pfn.
19 */
20 long (*direct_access)(struct dax_device *, pgoff_t, long,
21 void **, pfn_t *);
22 /* copy_from_iter: required operation for fs-dax direct-i/o */
23 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
24 struct iov_iter *);
25 /* copy_to_iter: required operation for fs-dax direct-i/o */
26 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
27 struct iov_iter *);
28};
29
30extern struct attribute_group dax_attribute_group;
31
32#if IS_ENABLED(CONFIG_DAX)
33struct dax_device *dax_get_by_host(const char *host);
34struct dax_device *alloc_dax(void *private, const char *host,
35 const struct dax_operations *ops);
36void put_dax(struct dax_device *dax_dev);
37void kill_dax(struct dax_device *dax_dev);
38void dax_write_cache(struct dax_device *dax_dev, bool wc);
39bool dax_write_cache_enabled(struct dax_device *dax_dev);
40#else
41static inline struct dax_device *dax_get_by_host(const char *host)
42{
43 return NULL;
44}
45static inline struct dax_device *alloc_dax(void *private, const char *host,
46 const struct dax_operations *ops)
47{
48 /*
49 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
50 * NULL is an error or expected.
51 */
52 return NULL;
53}
54static inline void put_dax(struct dax_device *dax_dev)
55{
56}
57static inline void kill_dax(struct dax_device *dax_dev)
58{
59}
60static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
61{
62}
63static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
64{
65 return false;
66}
67#endif
68
69struct writeback_control;
70int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
71#if IS_ENABLED(CONFIG_FS_DAX)
72bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
73static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
74{
75 return __bdev_dax_supported(bdev, blocksize);
76}
77
78static inline struct dax_device *fs_dax_get_by_host(const char *host)
79{
80 return dax_get_by_host(host);
81}
82
83static inline void fs_put_dax(struct dax_device *dax_dev)
84{
85 put_dax(dax_dev);
86}
87
88struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
89int dax_writeback_mapping_range(struct address_space *mapping,
90 struct block_device *bdev, struct writeback_control *wbc);
91
92struct page *dax_layout_busy_page(struct address_space *mapping);
93dax_entry_t dax_lock_page(struct page *page);
94void dax_unlock_page(struct page *page, dax_entry_t cookie);
95#else
96static inline bool bdev_dax_supported(struct block_device *bdev,
97 int blocksize)
98{
99 return false;
100}
101
102static inline struct dax_device *fs_dax_get_by_host(const char *host)
103{
104 return NULL;
105}
106
107static inline void fs_put_dax(struct dax_device *dax_dev)
108{
109}
110
111static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
112{
113 return NULL;
114}
115
116static inline struct page *dax_layout_busy_page(struct address_space *mapping)
117{
118 return NULL;
119}
120
121static inline int dax_writeback_mapping_range(struct address_space *mapping,
122 struct block_device *bdev, struct writeback_control *wbc)
123{
124 return -EOPNOTSUPP;
125}
126
127static inline dax_entry_t dax_lock_page(struct page *page)
128{
129 if (IS_DAX(page->mapping->host))
130 return ~0UL;
131 return 0;
132}
133
134static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
135{
136}
137#endif
138
139int dax_read_lock(void);
140void dax_read_unlock(int id);
141bool dax_alive(struct dax_device *dax_dev);
142void *dax_get_private(struct dax_device *dax_dev);
143long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
144 void **kaddr, pfn_t *pfn);
145size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
146 size_t bytes, struct iov_iter *i);
147size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
148 size_t bytes, struct iov_iter *i);
149void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
150
151ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
152 const struct iomap_ops *ops);
153vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
154 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
155vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
156 enum page_entry_size pe_size, pfn_t pfn);
157int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
158int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
159 pgoff_t index);
160
161#ifdef CONFIG_FS_DAX
162int __dax_zero_page_range(struct block_device *bdev,
163 struct dax_device *dax_dev, sector_t sector,
164 unsigned int offset, unsigned int length);
165#else
166static inline int __dax_zero_page_range(struct block_device *bdev,
167 struct dax_device *dax_dev, sector_t sector,
168 unsigned int offset, unsigned int length)
169{
170 return -ENXIO;
171}
172#endif
173
174static inline bool dax_mapping(struct address_space *mapping)
175{
176 return mapping->host && IS_DAX(mapping->host);
177}
178
179#endif
180