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
9typedef unsigned long dax_entry_t;
10
11struct dax_device;
12struct gendisk;
13struct iomap_ops;
14struct iomap_iter;
15struct iomap;
16
17enum dax_access_mode {
18 DAX_ACCESS,
19 DAX_RECOVERY_WRITE,
20};
21
22struct dax_operations {
23 /*
24 * direct_access: translate a device-relative
25 * logical-page-offset into an absolute physical pfn. Return the
26 * number of pages available for DAX at that pfn.
27 */
28 long (*direct_access)(struct dax_device *, pgoff_t, long,
29 enum dax_access_mode, void **, pfn_t *);
30 /*
31 * Validate whether this device is usable as an fsdax backing
32 * device.
33 */
34 bool (*dax_supported)(struct dax_device *, struct block_device *, int,
35 sector_t, sector_t);
36 /* zero_page_range: required operation. Zero page range */
37 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
38 /*
39 * recovery_write: recover a poisoned range by DAX device driver
40 * capable of clearing poison.
41 */
42 size_t (*recovery_write)(struct dax_device *dax_dev, pgoff_t pgoff,
43 void *addr, size_t bytes, struct iov_iter *iter);
44};
45
46#if IS_ENABLED(CONFIG_DAX)
47struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
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);
53void set_dax_synchronous(struct dax_device *dax_dev);
54size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
55 void *addr, size_t bytes, struct iov_iter *i);
56/*
57 * Check if given mapping is supported by the file / underlying device.
58 */
59static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
60 struct dax_device *dax_dev)
61{
62 if (!(vma->vm_flags & VM_SYNC))
63 return true;
64 if (!IS_DAX(file_inode(vma->vm_file)))
65 return false;
66 return dax_synchronous(dax_dev);
67}
68#else
69static inline struct dax_device *alloc_dax(void *private,
70 const struct dax_operations *ops)
71{
72 /*
73 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
74 * NULL is an error or expected.
75 */
76 return NULL;
77}
78static inline void put_dax(struct dax_device *dax_dev)
79{
80}
81static inline void kill_dax(struct dax_device *dax_dev)
82{
83}
84static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
85{
86}
87static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
88{
89 return false;
90}
91static inline bool dax_synchronous(struct dax_device *dax_dev)
92{
93 return true;
94}
95static inline void set_dax_synchronous(struct dax_device *dax_dev)
96{
97}
98static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
99 struct dax_device *dax_dev)
100{
101 return !(vma->vm_flags & VM_SYNC);
102}
103static inline size_t dax_recovery_write(struct dax_device *dax_dev,
104 pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
105{
106 return 0;
107}
108#endif
109
110void set_dax_nocache(struct dax_device *dax_dev);
111void set_dax_nomc(struct dax_device *dax_dev);
112
113struct writeback_control;
114#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
115int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
116void dax_remove_host(struct gendisk *disk);
117struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
118 u64 *start_off);
119static inline void fs_put_dax(struct dax_device *dax_dev)
120{
121 put_dax(dax_dev);
122}
123#else
124static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
125{
126 return 0;
127}
128static inline void dax_remove_host(struct gendisk *disk)
129{
130}
131static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
132 u64 *start_off)
133{
134 return NULL;
135}
136static inline void fs_put_dax(struct dax_device *dax_dev)
137{
138}
139#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
140
141#if IS_ENABLED(CONFIG_FS_DAX)
142int dax_writeback_mapping_range(struct address_space *mapping,
143 struct dax_device *dax_dev, struct writeback_control *wbc);
144
145struct page *dax_layout_busy_page(struct address_space *mapping);
146struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
147dax_entry_t dax_lock_page(struct page *page);
148void dax_unlock_page(struct page *page, dax_entry_t cookie);
149#else
150static inline struct page *dax_layout_busy_page(struct address_space *mapping)
151{
152 return NULL;
153}
154
155static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
156{
157 return NULL;
158}
159
160static inline int dax_writeback_mapping_range(struct address_space *mapping,
161 struct dax_device *dax_dev, struct writeback_control *wbc)
162{
163 return -EOPNOTSUPP;
164}
165
166static inline dax_entry_t dax_lock_page(struct page *page)
167{
168 if (IS_DAX(page->mapping->host))
169 return ~0UL;
170 return 0;
171}
172
173static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
174{
175}
176#endif
177
178int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
179 const struct iomap_ops *ops);
180int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
181 const struct iomap_ops *ops);
182
183#if IS_ENABLED(CONFIG_DAX)
184int dax_read_lock(void);
185void dax_read_unlock(int id);
186#else
187static inline int dax_read_lock(void)
188{
189 return 0;
190}
191
192static inline void dax_read_unlock(int id)
193{
194}
195#endif /* CONFIG_DAX */
196bool dax_alive(struct dax_device *dax_dev);
197void *dax_get_private(struct dax_device *dax_dev);
198long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
199 enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
200size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
201 size_t bytes, struct iov_iter *i);
202size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
203 size_t bytes, struct iov_iter *i);
204int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
205 size_t nr_pages);
206void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
207
208ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
209 const struct iomap_ops *ops);
210vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
211 pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
212vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
213 enum page_entry_size pe_size, pfn_t pfn);
214int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
215int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
216 pgoff_t index);
217static inline bool dax_mapping(struct address_space *mapping)
218{
219 return mapping->host && IS_DAX(mapping->host);
220}
221
222#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
223void hmem_register_device(int target_nid, struct resource *r);
224#else
225static inline void hmem_register_device(int target_nid, struct resource *r)
226{
227}
228#endif
229
230#endif