Linux kernel mirror (for testing)
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linux
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
10/* Flag for synchronous flush */
11#define DAXDEV_F_SYNC (1UL << 0)
12
13typedef unsigned long dax_entry_t;
14
15struct iomap_ops;
16struct iomap;
17struct dax_device;
18struct dax_operations {
19 /*
20 * direct_access: translate a device-relative
21 * logical-page-offset into an absolute physical pfn. Return the
22 * number of pages available for DAX at that pfn.
23 */
24 long (*direct_access)(struct dax_device *, pgoff_t, long,
25 void **, pfn_t *);
26 /*
27 * Validate whether this device is usable as an fsdax backing
28 * device.
29 */
30 bool (*dax_supported)(struct dax_device *, struct block_device *, int,
31 sector_t, sector_t);
32 /* copy_from_iter: required operation for fs-dax direct-i/o */
33 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
34 struct iov_iter *);
35 /* copy_to_iter: required operation for fs-dax direct-i/o */
36 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
37 struct iov_iter *);
38 /* zero_page_range: required operation. Zero page range */
39 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
40};
41
42extern struct attribute_group dax_attribute_group;
43
44#if IS_ENABLED(CONFIG_DAX)
45struct dax_device *dax_get_by_host(const char *host);
46struct dax_device *alloc_dax(void *private, const char *host,
47 const struct dax_operations *ops, unsigned long flags);
48void put_dax(struct dax_device *dax_dev);
49void kill_dax(struct dax_device *dax_dev);
50void dax_write_cache(struct dax_device *dax_dev, bool wc);
51bool dax_write_cache_enabled(struct dax_device *dax_dev);
52bool __dax_synchronous(struct dax_device *dax_dev);
53static inline bool dax_synchronous(struct dax_device *dax_dev)
54{
55 return __dax_synchronous(dax_dev);
56}
57void __set_dax_synchronous(struct dax_device *dax_dev);
58static inline void set_dax_synchronous(struct dax_device *dax_dev)
59{
60 __set_dax_synchronous(dax_dev);
61}
62/*
63 * Check if given mapping is supported by the file / underlying device.
64 */
65static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
66 struct dax_device *dax_dev)
67{
68 if (!(vma->vm_flags & VM_SYNC))
69 return true;
70 if (!IS_DAX(file_inode(vma->vm_file)))
71 return false;
72 return dax_synchronous(dax_dev);
73}
74#else
75static inline struct dax_device *dax_get_by_host(const char *host)
76{
77 return NULL;
78}
79static inline struct dax_device *alloc_dax(void *private, const char *host,
80 const struct dax_operations *ops, unsigned long flags)
81{
82 /*
83 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
84 * NULL is an error or expected.
85 */
86 return NULL;
87}
88static inline void put_dax(struct dax_device *dax_dev)
89{
90}
91static inline void kill_dax(struct dax_device *dax_dev)
92{
93}
94static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
95{
96}
97static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
98{
99 return false;
100}
101static inline bool dax_synchronous(struct dax_device *dax_dev)
102{
103 return true;
104}
105static inline void set_dax_synchronous(struct dax_device *dax_dev)
106{
107}
108static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
109 struct dax_device *dax_dev)
110{
111 return !(vma->vm_flags & VM_SYNC);
112}
113#endif
114
115struct writeback_control;
116int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
117#if IS_ENABLED(CONFIG_FS_DAX)
118bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
119static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
120{
121 return __bdev_dax_supported(bdev, blocksize);
122}
123
124bool __generic_fsdax_supported(struct dax_device *dax_dev,
125 struct block_device *bdev, int blocksize, sector_t start,
126 sector_t sectors);
127static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
128 struct block_device *bdev, int blocksize, sector_t start,
129 sector_t sectors)
130{
131 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
132 sectors);
133}
134
135static inline void fs_put_dax(struct dax_device *dax_dev)
136{
137 put_dax(dax_dev);
138}
139
140struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
141int dax_writeback_mapping_range(struct address_space *mapping,
142 struct dax_device *dax_dev, struct writeback_control *wbc);
143
144struct page *dax_layout_busy_page(struct address_space *mapping);
145dax_entry_t dax_lock_page(struct page *page);
146void dax_unlock_page(struct page *page, dax_entry_t cookie);
147#else
148static inline bool bdev_dax_supported(struct block_device *bdev,
149 int blocksize)
150{
151 return false;
152}
153
154static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
155 struct block_device *bdev, int blocksize, sector_t start,
156 sector_t sectors)
157{
158 return false;
159}
160
161static inline void fs_put_dax(struct dax_device *dax_dev)
162{
163}
164
165static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
166{
167 return NULL;
168}
169
170static inline struct page *dax_layout_busy_page(struct address_space *mapping)
171{
172 return NULL;
173}
174
175static inline int dax_writeback_mapping_range(struct address_space *mapping,
176 struct dax_device *dax_dev, struct writeback_control *wbc)
177{
178 return -EOPNOTSUPP;
179}
180
181static inline dax_entry_t dax_lock_page(struct page *page)
182{
183 if (IS_DAX(page->mapping->host))
184 return ~0UL;
185 return 0;
186}
187
188static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
189{
190}
191#endif
192
193int dax_read_lock(void);
194void dax_read_unlock(int id);
195bool dax_alive(struct dax_device *dax_dev);
196void *dax_get_private(struct dax_device *dax_dev);
197long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
198 void **kaddr, pfn_t *pfn);
199bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
200 int blocksize, sector_t start, sector_t len);
201size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
202 size_t bytes, struct iov_iter *i);
203size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
204 size_t bytes, struct iov_iter *i);
205int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
206 size_t nr_pages);
207void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
208
209ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
210 const struct iomap_ops *ops);
211vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
212 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
213vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
214 enum page_entry_size pe_size, pfn_t pfn);
215int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
216int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
217 pgoff_t index);
218int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size,
219 struct iomap *iomap);
220static inline bool dax_mapping(struct address_space *mapping)
221{
222 return mapping->host && IS_DAX(mapping->host);
223}
224
225#endif