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 dax_device;
17struct dax_operations {
18 /*
19 * direct_access: translate a device-relative
20 * logical-page-offset into an absolute physical pfn. Return the
21 * number of pages available for DAX at that pfn.
22 */
23 long (*direct_access)(struct dax_device *, pgoff_t, long,
24 void **, pfn_t *);
25 /*
26 * Validate whether this device is usable as an fsdax backing
27 * device.
28 */
29 bool (*dax_supported)(struct dax_device *, struct block_device *, int,
30 sector_t, sector_t);
31 /* copy_from_iter: required operation for fs-dax direct-i/o */
32 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
33 struct iov_iter *);
34 /* copy_to_iter: required operation for fs-dax direct-i/o */
35 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
36 struct iov_iter *);
37};
38
39extern struct attribute_group dax_attribute_group;
40
41#if IS_ENABLED(CONFIG_DAX)
42struct dax_device *dax_get_by_host(const char *host);
43struct dax_device *alloc_dax(void *private, const char *host,
44 const struct dax_operations *ops, unsigned long flags);
45void put_dax(struct dax_device *dax_dev);
46void kill_dax(struct dax_device *dax_dev);
47void dax_write_cache(struct dax_device *dax_dev, bool wc);
48bool dax_write_cache_enabled(struct dax_device *dax_dev);
49bool __dax_synchronous(struct dax_device *dax_dev);
50static inline bool dax_synchronous(struct dax_device *dax_dev)
51{
52 return __dax_synchronous(dax_dev);
53}
54void __set_dax_synchronous(struct dax_device *dax_dev);
55static inline void set_dax_synchronous(struct dax_device *dax_dev)
56{
57 __set_dax_synchronous(dax_dev);
58}
59/*
60 * Check if given mapping is supported by the file / underlying device.
61 */
62static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
63 struct dax_device *dax_dev)
64{
65 if (!(vma->vm_flags & VM_SYNC))
66 return true;
67 if (!IS_DAX(file_inode(vma->vm_file)))
68 return false;
69 return dax_synchronous(dax_dev);
70}
71#else
72static inline struct dax_device *dax_get_by_host(const char *host)
73{
74 return NULL;
75}
76static inline struct dax_device *alloc_dax(void *private, const char *host,
77 const struct dax_operations *ops, unsigned long flags)
78{
79 /*
80 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
81 * NULL is an error or expected.
82 */
83 return NULL;
84}
85static inline void put_dax(struct dax_device *dax_dev)
86{
87}
88static inline void kill_dax(struct dax_device *dax_dev)
89{
90}
91static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
92{
93}
94static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
95{
96 return false;
97}
98static inline bool dax_synchronous(struct dax_device *dax_dev)
99{
100 return true;
101}
102static inline void set_dax_synchronous(struct dax_device *dax_dev)
103{
104}
105static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
106 struct dax_device *dax_dev)
107{
108 return !(vma->vm_flags & VM_SYNC);
109}
110#endif
111
112struct writeback_control;
113int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
114#if IS_ENABLED(CONFIG_FS_DAX)
115bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
116static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
117{
118 return __bdev_dax_supported(bdev, blocksize);
119}
120
121bool __generic_fsdax_supported(struct dax_device *dax_dev,
122 struct block_device *bdev, int blocksize, sector_t start,
123 sector_t sectors);
124static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
125 struct block_device *bdev, int blocksize, sector_t start,
126 sector_t sectors)
127{
128 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
129 sectors);
130}
131
132static inline void fs_put_dax(struct dax_device *dax_dev)
133{
134 put_dax(dax_dev);
135}
136
137struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
138int dax_writeback_mapping_range(struct address_space *mapping,
139 struct dax_device *dax_dev, struct writeback_control *wbc);
140
141struct page *dax_layout_busy_page(struct address_space *mapping);
142dax_entry_t dax_lock_page(struct page *page);
143void dax_unlock_page(struct page *page, dax_entry_t cookie);
144#else
145static inline bool bdev_dax_supported(struct block_device *bdev,
146 int blocksize)
147{
148 return false;
149}
150
151static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
152 struct block_device *bdev, int blocksize, sector_t start,
153 sector_t sectors)
154{
155 return false;
156}
157
158static inline void fs_put_dax(struct dax_device *dax_dev)
159{
160}
161
162static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
163{
164 return NULL;
165}
166
167static inline struct page *dax_layout_busy_page(struct address_space *mapping)
168{
169 return NULL;
170}
171
172static inline int dax_writeback_mapping_range(struct address_space *mapping,
173 struct dax_device *dax_dev, struct writeback_control *wbc)
174{
175 return -EOPNOTSUPP;
176}
177
178static inline dax_entry_t dax_lock_page(struct page *page)
179{
180 if (IS_DAX(page->mapping->host))
181 return ~0UL;
182 return 0;
183}
184
185static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
186{
187}
188#endif
189
190int dax_read_lock(void);
191void dax_read_unlock(int id);
192bool dax_alive(struct dax_device *dax_dev);
193void *dax_get_private(struct dax_device *dax_dev);
194long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
195 void **kaddr, pfn_t *pfn);
196bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
197 int blocksize, sector_t start, sector_t len);
198size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
199 size_t bytes, struct iov_iter *i);
200size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
201 size_t bytes, struct iov_iter *i);
202void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
203
204ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
205 const struct iomap_ops *ops);
206vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
207 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
208vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
209 enum page_entry_size pe_size, pfn_t pfn);
210int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
211int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
212 pgoff_t index);
213
214#ifdef CONFIG_FS_DAX
215int __dax_zero_page_range(struct block_device *bdev,
216 struct dax_device *dax_dev, sector_t sector,
217 unsigned int offset, unsigned int length);
218#else
219static inline int __dax_zero_page_range(struct block_device *bdev,
220 struct dax_device *dax_dev, sector_t sector,
221 unsigned int offset, unsigned int length)
222{
223 return -ENXIO;
224}
225#endif
226
227static inline bool dax_mapping(struct address_space *mapping)
228{
229 return mapping->host && IS_DAX(mapping->host);
230}
231
232#endif