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
46struct dax_holder_operations {
47	/*
48	 * notify_failure - notify memory failure into inner holder device
49	 * @dax_dev: the dax device which contains the holder
50	 * @offset: offset on this dax device where memory failure occurs
51	 * @len: length of this memory failure event
52	 * @flags: action flags for memory failure handler
53	 */
54	int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
55			u64 len, int mf_flags);
56};
57
58#if IS_ENABLED(CONFIG_DAX)
59struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
60void *dax_holder(struct dax_device *dax_dev);
61void put_dax(struct dax_device *dax_dev);
62void kill_dax(struct dax_device *dax_dev);
63void dax_write_cache(struct dax_device *dax_dev, bool wc);
64bool dax_write_cache_enabled(struct dax_device *dax_dev);
65bool dax_synchronous(struct dax_device *dax_dev);
66void set_dax_nocache(struct dax_device *dax_dev);
67void set_dax_nomc(struct dax_device *dax_dev);
68void set_dax_synchronous(struct dax_device *dax_dev);
69size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
70		void *addr, size_t bytes, struct iov_iter *i);
71/*
72 * Check if given mapping is supported by the file / underlying device.
73 */
74static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
75					     struct dax_device *dax_dev)
76{
77	if (!(vma->vm_flags & VM_SYNC))
78		return true;
79	if (!IS_DAX(file_inode(vma->vm_file)))
80		return false;
81	return dax_synchronous(dax_dev);
82}
83#else
84static inline void *dax_holder(struct dax_device *dax_dev)
85{
86	return NULL;
87}
88static inline struct dax_device *alloc_dax(void *private,
89		const struct dax_operations *ops)
90{
91	return ERR_PTR(-EOPNOTSUPP);
92}
93static inline void put_dax(struct dax_device *dax_dev)
94{
95}
96static inline void kill_dax(struct dax_device *dax_dev)
97{
98}
99static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
100{
101}
102static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
103{
104	return false;
105}
106static inline bool dax_synchronous(struct dax_device *dax_dev)
107{
108	return true;
109}
110static inline void set_dax_nocache(struct dax_device *dax_dev)
111{
112}
113static inline void set_dax_nomc(struct dax_device *dax_dev)
114{
115}
116static inline void set_dax_synchronous(struct dax_device *dax_dev)
117{
118}
119static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
120				struct dax_device *dax_dev)
121{
122	return !(vma->vm_flags & VM_SYNC);
123}
124static inline size_t dax_recovery_write(struct dax_device *dax_dev,
125		pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
126{
127	return 0;
128}
129#endif
130
131struct writeback_control;
132#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
133int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
134void dax_remove_host(struct gendisk *disk);
135struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
136		void *holder, const struct dax_holder_operations *ops);
137void fs_put_dax(struct dax_device *dax_dev, void *holder);
138#else
139static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
140{
141	return 0;
142}
143static inline void dax_remove_host(struct gendisk *disk)
144{
145}
146static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
147		u64 *start_off, void *holder,
148		const struct dax_holder_operations *ops)
149{
150	return NULL;
151}
152static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
153{
154}
155#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
156
157#if IS_ENABLED(CONFIG_FS_DAX)
158int dax_writeback_mapping_range(struct address_space *mapping,
159		struct dax_device *dax_dev, struct writeback_control *wbc);
160
161struct page *dax_layout_busy_page(struct address_space *mapping);
162struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
163dax_entry_t dax_lock_folio(struct folio *folio);
164void dax_unlock_folio(struct folio *folio, dax_entry_t cookie);
165dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
166		unsigned long index, struct page **page);
167void dax_unlock_mapping_entry(struct address_space *mapping,
168		unsigned long index, dax_entry_t cookie);
169#else
170static inline struct page *dax_layout_busy_page(struct address_space *mapping)
171{
172	return NULL;
173}
174
175static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
176{
177	return NULL;
178}
179
180static inline int dax_writeback_mapping_range(struct address_space *mapping,
181		struct dax_device *dax_dev, struct writeback_control *wbc)
182{
183	return -EOPNOTSUPP;
184}
185
186static inline dax_entry_t dax_lock_folio(struct folio *folio)
187{
188	if (IS_DAX(folio->mapping->host))
189		return ~0UL;
190	return 0;
191}
192
193static inline void dax_unlock_folio(struct folio *folio, dax_entry_t cookie)
194{
195}
196
197static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
198		unsigned long index, struct page **page)
199{
200	return 0;
201}
202
203static inline void dax_unlock_mapping_entry(struct address_space *mapping,
204		unsigned long index, dax_entry_t cookie)
205{
206}
207#endif
208
209int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
210		const struct iomap_ops *ops);
211int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
212		const struct iomap_ops *ops);
213int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
214		const struct iomap_ops *ops);
215
216#if IS_ENABLED(CONFIG_DAX)
217int dax_read_lock(void);
218void dax_read_unlock(int id);
219#else
220static inline int dax_read_lock(void)
221{
222	return 0;
223}
224
225static inline void dax_read_unlock(int id)
226{
227}
228#endif /* CONFIG_DAX */
229bool dax_alive(struct dax_device *dax_dev);
230void *dax_get_private(struct dax_device *dax_dev);
231long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
232		enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
233size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
234		size_t bytes, struct iov_iter *i);
235size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
236		size_t bytes, struct iov_iter *i);
237int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
238			size_t nr_pages);
239int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
240		int mf_flags);
241void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
242
243ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
244		const struct iomap_ops *ops);
245vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
246		    pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
247vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
248		unsigned int order, pfn_t pfn);
249int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
250int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
251				      pgoff_t index);
252int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
253				  struct inode *dest, loff_t destoff,
254				  loff_t len, bool *is_same,
255				  const struct iomap_ops *ops);
256int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
257			      struct file *file_out, loff_t pos_out,
258			      loff_t *len, unsigned int remap_flags,
259			      const struct iomap_ops *ops);
260static inline bool dax_mapping(struct address_space *mapping)
261{
262	return mapping->host && IS_DAX(mapping->host);
263}
264
265/*
266 * Due to dax's memory and block duo personalities, hwpoison reporting
267 * takes into consideration which personality is presently visible.
268 * When dax acts like a block device, such as in block IO, an encounter of
269 * dax hwpoison is reported as -EIO.
270 * When dax acts like memory, such as in page fault, a detection of hwpoison
271 * is reported as -EHWPOISON which leads to VM_FAULT_HWPOISON.
272 */
273static inline int dax_mem2blk_err(int err)
274{
275	return (err == -EHWPOISON) ? -EIO : err;
276}
277
278#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
279void hmem_register_resource(int target_nid, struct resource *r);
280#else
281static inline void hmem_register_resource(int target_nid, struct resource *r)
282{
283}
284#endif
285
286typedef int (*walk_hmem_fn)(struct device *dev, int target_nid,
287			    const struct resource *res);
288int walk_hmem_resources(struct device *dev, walk_hmem_fn fn);
289#endif
290