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 13 typedef unsigned long dax_entry_t; 14 15 struct iomap_ops; 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 }; 38 39 extern struct attribute_group dax_attribute_group; 40 41 #if IS_ENABLED(CONFIG_DAX) 42 struct dax_device *dax_get_by_host(const char *host); 43 struct dax_device *alloc_dax(void *private, const char *host, 44 const struct dax_operations *ops, unsigned long flags); 45 void put_dax(struct dax_device *dax_dev); 46 void kill_dax(struct dax_device *dax_dev); 47 void dax_write_cache(struct dax_device *dax_dev, bool wc); 48 bool dax_write_cache_enabled(struct dax_device *dax_dev); 49 bool __dax_synchronous(struct dax_device *dax_dev); 50 static inline bool dax_synchronous(struct dax_device *dax_dev) 51 { 52 return __dax_synchronous(dax_dev); 53 } 54 void __set_dax_synchronous(struct dax_device *dax_dev); 55 static 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 */ 62 static 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 72 static inline struct dax_device *dax_get_by_host(const char *host) 73 { 74 return NULL; 75 } 76 static 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 } 85 static inline void put_dax(struct dax_device *dax_dev) 86 { 87 } 88 static inline void kill_dax(struct dax_device *dax_dev) 89 { 90 } 91 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc) 92 { 93 } 94 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) 95 { 96 return false; 97 } 98 static inline bool dax_synchronous(struct dax_device *dax_dev) 99 { 100 return true; 101 } 102 static inline void set_dax_synchronous(struct dax_device *dax_dev) 103 { 104 } 105 static 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 111 112 struct writeback_control; 113 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); 114 #if IS_ENABLED(CONFIG_FS_DAX) 115 bool __bdev_dax_supported(struct block_device *bdev, int blocksize); 116 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize) 117 { 118 return __bdev_dax_supported(bdev, blocksize); 119 } 120 121 bool __generic_fsdax_supported(struct dax_device *dax_dev, 122 struct block_device *bdev, int blocksize, sector_t start, 123 sector_t sectors); 124 static 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 } 131 132 static inline struct dax_device *fs_dax_get_by_host(const char *host) 133 { 134 return dax_get_by_host(host); 135 } 136 137 static inline void fs_put_dax(struct dax_device *dax_dev) 138 { 139 put_dax(dax_dev); 140 } 141 142 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); 143 int dax_writeback_mapping_range(struct address_space *mapping, 144 struct block_device *bdev, struct writeback_control *wbc); 145 146 struct page *dax_layout_busy_page(struct address_space *mapping); 147 dax_entry_t dax_lock_page(struct page *page); 148 void dax_unlock_page(struct page *page, dax_entry_t cookie); 149 #else 150 static inline bool bdev_dax_supported(struct block_device *bdev, 151 int blocksize) 152 { 153 return false; 154 } 155 156 static inline bool generic_fsdax_supported(struct dax_device *dax_dev, 157 struct block_device *bdev, int blocksize, sector_t start, 158 sector_t sectors) 159 { 160 return false; 161 } 162 163 static inline struct dax_device *fs_dax_get_by_host(const char *host) 164 { 165 return NULL; 166 } 167 168 static inline void fs_put_dax(struct dax_device *dax_dev) 169 { 170 } 171 172 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 173 { 174 return NULL; 175 } 176 177 static inline struct page *dax_layout_busy_page(struct address_space *mapping) 178 { 179 return NULL; 180 } 181 182 static inline int dax_writeback_mapping_range(struct address_space *mapping, 183 struct block_device *bdev, struct writeback_control *wbc) 184 { 185 return -EOPNOTSUPP; 186 } 187 188 static inline dax_entry_t dax_lock_page(struct page *page) 189 { 190 if (IS_DAX(page->mapping->host)) 191 return ~0UL; 192 return 0; 193 } 194 195 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) 196 { 197 } 198 #endif 199 200 int dax_read_lock(void); 201 void dax_read_unlock(int id); 202 bool dax_alive(struct dax_device *dax_dev); 203 void *dax_get_private(struct dax_device *dax_dev); 204 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 205 void **kaddr, pfn_t *pfn); 206 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 207 int blocksize, sector_t start, sector_t len); 208 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 209 size_t bytes, struct iov_iter *i); 210 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 211 size_t bytes, struct iov_iter *i); 212 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); 213 214 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 215 const struct iomap_ops *ops); 216 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 217 pfn_t *pfnp, int *errp, const struct iomap_ops *ops); 218 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 219 enum page_entry_size pe_size, pfn_t pfn); 220 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 221 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 222 pgoff_t index); 223 224 #ifdef CONFIG_FS_DAX 225 int __dax_zero_page_range(struct block_device *bdev, 226 struct dax_device *dax_dev, sector_t sector, 227 unsigned int offset, unsigned int length); 228 #else 229 static inline int __dax_zero_page_range(struct block_device *bdev, 230 struct dax_device *dax_dev, sector_t sector, 231 unsigned int offset, unsigned int length) 232 { 233 return -ENXIO; 234 } 235 #endif 236 237 static inline bool dax_mapping(struct address_space *mapping) 238 { 239 return mapping->host && IS_DAX(mapping->host); 240 } 241 242 #endif 243