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 typedef unsigned long dax_entry_t; 11 12 struct iomap_ops; 13 struct dax_device; 14 struct dax_operations { 15 /* 16 * direct_access: translate a device-relative 17 * logical-page-offset into an absolute physical pfn. Return the 18 * number of pages available for DAX at that pfn. 19 */ 20 long (*direct_access)(struct dax_device *, pgoff_t, long, 21 void **, pfn_t *); 22 /* 23 * Validate whether this device is usable as an fsdax backing 24 * device. 25 */ 26 bool (*dax_supported)(struct dax_device *, struct block_device *, int, 27 sector_t, sector_t); 28 /* copy_from_iter: required operation for fs-dax direct-i/o */ 29 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t, 30 struct iov_iter *); 31 /* copy_to_iter: required operation for fs-dax direct-i/o */ 32 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t, 33 struct iov_iter *); 34 }; 35 36 extern struct attribute_group dax_attribute_group; 37 38 #if IS_ENABLED(CONFIG_DAX) 39 struct dax_device *dax_get_by_host(const char *host); 40 struct dax_device *alloc_dax(void *private, const char *host, 41 const struct dax_operations *ops); 42 void put_dax(struct dax_device *dax_dev); 43 void kill_dax(struct dax_device *dax_dev); 44 void dax_write_cache(struct dax_device *dax_dev, bool wc); 45 bool dax_write_cache_enabled(struct dax_device *dax_dev); 46 #else 47 static inline struct dax_device *dax_get_by_host(const char *host) 48 { 49 return NULL; 50 } 51 static inline struct dax_device *alloc_dax(void *private, const char *host, 52 const struct dax_operations *ops) 53 { 54 /* 55 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this 56 * NULL is an error or expected. 57 */ 58 return NULL; 59 } 60 static inline void put_dax(struct dax_device *dax_dev) 61 { 62 } 63 static inline void kill_dax(struct dax_device *dax_dev) 64 { 65 } 66 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc) 67 { 68 } 69 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) 70 { 71 return false; 72 } 73 #endif 74 75 struct writeback_control; 76 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); 77 #if IS_ENABLED(CONFIG_FS_DAX) 78 bool __bdev_dax_supported(struct block_device *bdev, int blocksize); 79 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize) 80 { 81 return __bdev_dax_supported(bdev, blocksize); 82 } 83 84 bool __generic_fsdax_supported(struct dax_device *dax_dev, 85 struct block_device *bdev, int blocksize, sector_t start, 86 sector_t sectors); 87 static inline bool generic_fsdax_supported(struct dax_device *dax_dev, 88 struct block_device *bdev, int blocksize, sector_t start, 89 sector_t sectors) 90 { 91 return __generic_fsdax_supported(dax_dev, bdev, blocksize, start, 92 sectors); 93 } 94 95 static inline struct dax_device *fs_dax_get_by_host(const char *host) 96 { 97 return dax_get_by_host(host); 98 } 99 100 static inline void fs_put_dax(struct dax_device *dax_dev) 101 { 102 put_dax(dax_dev); 103 } 104 105 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); 106 int dax_writeback_mapping_range(struct address_space *mapping, 107 struct block_device *bdev, struct writeback_control *wbc); 108 109 struct page *dax_layout_busy_page(struct address_space *mapping); 110 dax_entry_t dax_lock_page(struct page *page); 111 void dax_unlock_page(struct page *page, dax_entry_t cookie); 112 #else 113 static inline bool bdev_dax_supported(struct block_device *bdev, 114 int blocksize) 115 { 116 return false; 117 } 118 119 static inline bool generic_fsdax_supported(struct dax_device *dax_dev, 120 struct block_device *bdev, int blocksize, sector_t start, 121 sector_t sectors) 122 { 123 return false; 124 } 125 126 static inline struct dax_device *fs_dax_get_by_host(const char *host) 127 { 128 return NULL; 129 } 130 131 static inline void fs_put_dax(struct dax_device *dax_dev) 132 { 133 } 134 135 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 136 { 137 return NULL; 138 } 139 140 static inline struct page *dax_layout_busy_page(struct address_space *mapping) 141 { 142 return NULL; 143 } 144 145 static inline int dax_writeback_mapping_range(struct address_space *mapping, 146 struct block_device *bdev, struct writeback_control *wbc) 147 { 148 return -EOPNOTSUPP; 149 } 150 151 static inline dax_entry_t dax_lock_page(struct page *page) 152 { 153 if (IS_DAX(page->mapping->host)) 154 return ~0UL; 155 return 0; 156 } 157 158 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) 159 { 160 } 161 #endif 162 163 int dax_read_lock(void); 164 void dax_read_unlock(int id); 165 bool dax_alive(struct dax_device *dax_dev); 166 void *dax_get_private(struct dax_device *dax_dev); 167 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 168 void **kaddr, pfn_t *pfn); 169 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 170 int blocksize, sector_t start, sector_t len); 171 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 172 size_t bytes, struct iov_iter *i); 173 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 174 size_t bytes, struct iov_iter *i); 175 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); 176 177 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 178 const struct iomap_ops *ops); 179 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 180 pfn_t *pfnp, int *errp, const struct iomap_ops *ops); 181 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 182 enum page_entry_size pe_size, pfn_t pfn); 183 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 184 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 185 pgoff_t index); 186 187 #ifdef CONFIG_FS_DAX 188 int __dax_zero_page_range(struct block_device *bdev, 189 struct dax_device *dax_dev, sector_t sector, 190 unsigned int offset, unsigned int length); 191 #else 192 static inline int __dax_zero_page_range(struct block_device *bdev, 193 struct dax_device *dax_dev, sector_t sector, 194 unsigned int offset, unsigned int length) 195 { 196 return -ENXIO; 197 } 198 #endif 199 200 static inline bool dax_mapping(struct address_space *mapping) 201 { 202 return mapping->host && IS_DAX(mapping->host); 203 } 204 205 #endif 206