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 12 typedef unsigned long dax_entry_t; 13 14 struct iomap_ops; 15 struct iomap; 16 struct dax_device; 17 struct 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 extern struct attribute_group dax_attribute_group; 42 43 #if IS_ENABLED(CONFIG_DAX) 44 struct dax_device *dax_get_by_host(const char *host); 45 struct dax_device *alloc_dax(void *private, const char *host, 46 const struct dax_operations *ops, unsigned long flags); 47 void put_dax(struct dax_device *dax_dev); 48 void kill_dax(struct dax_device *dax_dev); 49 void dax_write_cache(struct dax_device *dax_dev, bool wc); 50 bool dax_write_cache_enabled(struct dax_device *dax_dev); 51 bool __dax_synchronous(struct dax_device *dax_dev); 52 static inline bool dax_synchronous(struct dax_device *dax_dev) 53 { 54 return __dax_synchronous(dax_dev); 55 } 56 void __set_dax_synchronous(struct dax_device *dax_dev); 57 static inline void set_dax_synchronous(struct dax_device *dax_dev) 58 { 59 __set_dax_synchronous(dax_dev); 60 } 61 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 62 int blocksize, sector_t start, sector_t len); 63 /* 64 * Check if given mapping is supported by the file / underlying device. 65 */ 66 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 67 struct dax_device *dax_dev) 68 { 69 if (!(vma->vm_flags & VM_SYNC)) 70 return true; 71 if (!IS_DAX(file_inode(vma->vm_file))) 72 return false; 73 return dax_synchronous(dax_dev); 74 } 75 #else 76 static inline struct dax_device *dax_get_by_host(const char *host) 77 { 78 return NULL; 79 } 80 static inline struct dax_device *alloc_dax(void *private, const char *host, 81 const struct dax_operations *ops, unsigned long flags) 82 { 83 /* 84 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this 85 * NULL is an error or expected. 86 */ 87 return NULL; 88 } 89 static inline void put_dax(struct dax_device *dax_dev) 90 { 91 } 92 static inline void kill_dax(struct dax_device *dax_dev) 93 { 94 } 95 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc) 96 { 97 } 98 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) 99 { 100 return false; 101 } 102 static inline bool dax_synchronous(struct dax_device *dax_dev) 103 { 104 return true; 105 } 106 static inline void set_dax_synchronous(struct dax_device *dax_dev) 107 { 108 } 109 static inline bool dax_supported(struct dax_device *dax_dev, 110 struct block_device *bdev, int blocksize, sector_t start, 111 sector_t len) 112 { 113 return false; 114 } 115 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 116 struct dax_device *dax_dev) 117 { 118 return !(vma->vm_flags & VM_SYNC); 119 } 120 #endif 121 122 struct writeback_control; 123 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); 124 #if IS_ENABLED(CONFIG_FS_DAX) 125 bool __bdev_dax_supported(struct block_device *bdev, int blocksize); 126 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize) 127 { 128 return __bdev_dax_supported(bdev, blocksize); 129 } 130 131 bool __generic_fsdax_supported(struct dax_device *dax_dev, 132 struct block_device *bdev, int blocksize, sector_t start, 133 sector_t sectors); 134 static inline bool generic_fsdax_supported(struct dax_device *dax_dev, 135 struct block_device *bdev, int blocksize, sector_t start, 136 sector_t sectors) 137 { 138 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start, 139 sectors); 140 } 141 142 static inline void fs_put_dax(struct dax_device *dax_dev) 143 { 144 put_dax(dax_dev); 145 } 146 147 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); 148 int dax_writeback_mapping_range(struct address_space *mapping, 149 struct dax_device *dax_dev, struct writeback_control *wbc); 150 151 struct page *dax_layout_busy_page(struct address_space *mapping); 152 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); 153 dax_entry_t dax_lock_page(struct page *page); 154 void dax_unlock_page(struct page *page, dax_entry_t cookie); 155 #else 156 static inline bool bdev_dax_supported(struct block_device *bdev, 157 int blocksize) 158 { 159 return false; 160 } 161 162 static inline bool generic_fsdax_supported(struct dax_device *dax_dev, 163 struct block_device *bdev, int blocksize, sector_t start, 164 sector_t sectors) 165 { 166 return false; 167 } 168 169 static inline void fs_put_dax(struct dax_device *dax_dev) 170 { 171 } 172 173 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 174 { 175 return NULL; 176 } 177 178 static inline struct page *dax_layout_busy_page(struct address_space *mapping) 179 { 180 return NULL; 181 } 182 183 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages) 184 { 185 return NULL; 186 } 187 188 static inline int dax_writeback_mapping_range(struct address_space *mapping, 189 struct dax_device *dax_dev, struct writeback_control *wbc) 190 { 191 return -EOPNOTSUPP; 192 } 193 194 static inline dax_entry_t dax_lock_page(struct page *page) 195 { 196 if (IS_DAX(page->mapping->host)) 197 return ~0UL; 198 return 0; 199 } 200 201 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) 202 { 203 } 204 #endif 205 206 #if IS_ENABLED(CONFIG_DAX) 207 int dax_read_lock(void); 208 void dax_read_unlock(int id); 209 #else 210 static inline int dax_read_lock(void) 211 { 212 return 0; 213 } 214 215 static inline void dax_read_unlock(int id) 216 { 217 } 218 #endif /* CONFIG_DAX */ 219 bool dax_alive(struct dax_device *dax_dev); 220 void *dax_get_private(struct dax_device *dax_dev); 221 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 222 void **kaddr, pfn_t *pfn); 223 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 224 size_t bytes, struct iov_iter *i); 225 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 226 size_t bytes, struct iov_iter *i); 227 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 228 size_t nr_pages); 229 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); 230 231 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 232 const struct iomap_ops *ops); 233 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 234 pfn_t *pfnp, int *errp, const struct iomap_ops *ops); 235 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 236 enum page_entry_size pe_size, pfn_t pfn); 237 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 238 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 239 pgoff_t index); 240 s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap); 241 static inline bool dax_mapping(struct address_space *mapping) 242 { 243 return mapping->host && IS_DAX(mapping->host); 244 } 245 246 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES 247 void hmem_register_device(int target_nid, struct resource *r); 248 #else 249 static inline void hmem_register_device(int target_nid, struct resource *r) 250 { 251 } 252 #endif 253 254 #endif 255