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
9/* Flag for synchronous flush */
10#define DAXDEV_F_SYNC (1UL << 0)
11
12typedef unsigned long dax_entry_t;
13
14struct iomap_ops;
15struct iomap;
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 /* zero_page_range: required operation. Zero page range */
38 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
39};
40
41#if IS_ENABLED(CONFIG_DAX)
42struct dax_device *alloc_dax(void *private, const char *host,
43 const struct dax_operations *ops, unsigned long flags);
44void put_dax(struct dax_device *dax_dev);
45void kill_dax(struct dax_device *dax_dev);
46void dax_write_cache(struct dax_device *dax_dev, bool wc);
47bool dax_write_cache_enabled(struct dax_device *dax_dev);
48bool __dax_synchronous(struct dax_device *dax_dev);
49static inline bool dax_synchronous(struct dax_device *dax_dev)
50{
51 return __dax_synchronous(dax_dev);
52}
53void __set_dax_synchronous(struct dax_device *dax_dev);
54static inline void set_dax_synchronous(struct dax_device *dax_dev)
55{
56 __set_dax_synchronous(dax_dev);
57}
58/*
59 * Check if given mapping is supported by the file / underlying device.
60 */
61static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
62 struct dax_device *dax_dev)
63{
64 if (!(vma->vm_flags & VM_SYNC))
65 return true;
66 if (!IS_DAX(file_inode(vma->vm_file)))
67 return false;
68 return dax_synchronous(dax_dev);
69}
70#else
71static inline struct dax_device *alloc_dax(void *private, const char *host,
72 const struct dax_operations *ops, unsigned long flags)
73{
74 /*
75 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
76 * NULL is an error or expected.
77 */
78 return NULL;
79}
80static inline void put_dax(struct dax_device *dax_dev)
81{
82}
83static inline void kill_dax(struct dax_device *dax_dev)
84{
85}
86static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
87{
88}
89static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
90{
91 return false;
92}
93static inline bool dax_synchronous(struct dax_device *dax_dev)
94{
95 return true;
96}
97static inline void set_dax_synchronous(struct dax_device *dax_dev)
98{
99}
100static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
101 struct dax_device *dax_dev)
102{
103 return !(vma->vm_flags & VM_SYNC);
104}
105#endif
106
107struct writeback_control;
108int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
109#if IS_ENABLED(CONFIG_FS_DAX)
110bool generic_fsdax_supported(struct dax_device *dax_dev,
111 struct block_device *bdev, int blocksize, sector_t start,
112 sector_t sectors);
113
114bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
115 int blocksize, sector_t start, sector_t len);
116
117static inline void fs_put_dax(struct dax_device *dax_dev)
118{
119 put_dax(dax_dev);
120}
121
122struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
123int dax_writeback_mapping_range(struct address_space *mapping,
124 struct dax_device *dax_dev, struct writeback_control *wbc);
125
126struct page *dax_layout_busy_page(struct address_space *mapping);
127struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
128dax_entry_t dax_lock_page(struct page *page);
129void dax_unlock_page(struct page *page, dax_entry_t cookie);
130#else
131#define generic_fsdax_supported NULL
132
133static inline bool dax_supported(struct dax_device *dax_dev,
134 struct block_device *bdev, int blocksize, sector_t start,
135 sector_t len)
136{
137 return false;
138}
139
140static inline void fs_put_dax(struct dax_device *dax_dev)
141{
142}
143
144static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
145{
146 return NULL;
147}
148
149static inline struct page *dax_layout_busy_page(struct address_space *mapping)
150{
151 return NULL;
152}
153
154static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
155{
156 return NULL;
157}
158
159static inline int dax_writeback_mapping_range(struct address_space *mapping,
160 struct dax_device *dax_dev, struct writeback_control *wbc)
161{
162 return -EOPNOTSUPP;
163}
164
165static inline dax_entry_t dax_lock_page(struct page *page)
166{
167 if (IS_DAX(page->mapping->host))
168 return ~0UL;
169 return 0;
170}
171
172static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
173{
174}
175#endif
176
177#if IS_ENABLED(CONFIG_DAX)
178int dax_read_lock(void);
179void dax_read_unlock(int id);
180#else
181static inline int dax_read_lock(void)
182{
183 return 0;
184}
185
186static inline void dax_read_unlock(int id)
187{
188}
189#endif /* CONFIG_DAX */
190bool dax_alive(struct dax_device *dax_dev);
191void *dax_get_private(struct dax_device *dax_dev);
192long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
193 void **kaddr, pfn_t *pfn);
194size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
195 size_t bytes, struct iov_iter *i);
196size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
197 size_t bytes, struct iov_iter *i);
198int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
199 size_t nr_pages);
200void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
201
202ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
203 const struct iomap_ops *ops);
204vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
205 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
206vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
207 enum page_entry_size pe_size, pfn_t pfn);
208int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
209int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
210 pgoff_t index);
211s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap);
212static inline bool dax_mapping(struct address_space *mapping)
213{
214 return mapping->host && IS_DAX(mapping->host);
215}
216
217#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
218void hmem_register_device(int target_nid, struct resource *r);
219#else
220static inline void hmem_register_device(int target_nid, struct resource *r)
221{
222}
223#endif
224
225#endif