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