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 typedef unsigned long dax_entry_t; 10 11 struct dax_device; 12 struct gendisk; 13 struct iomap_ops; 14 struct iomap_iter; 15 struct iomap; 16 17 enum dax_access_mode { 18 DAX_ACCESS, 19 DAX_RECOVERY_WRITE, 20 }; 21 22 struct 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 40 #if IS_ENABLED(CONFIG_DAX) 41 struct dax_device *alloc_dax(void *private, 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 bool dax_synchronous(struct dax_device *dax_dev); 47 void set_dax_synchronous(struct dax_device *dax_dev); 48 /* 49 * Check if given mapping is supported by the file / underlying device. 50 */ 51 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 52 struct dax_device *dax_dev) 53 { 54 if (!(vma->vm_flags & VM_SYNC)) 55 return true; 56 if (!IS_DAX(file_inode(vma->vm_file))) 57 return false; 58 return dax_synchronous(dax_dev); 59 } 60 #else 61 static inline struct dax_device *alloc_dax(void *private, 62 const struct dax_operations *ops) 63 { 64 /* 65 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this 66 * NULL is an error or expected. 67 */ 68 return NULL; 69 } 70 static inline void put_dax(struct dax_device *dax_dev) 71 { 72 } 73 static inline void kill_dax(struct dax_device *dax_dev) 74 { 75 } 76 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc) 77 { 78 } 79 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) 80 { 81 return false; 82 } 83 static inline bool dax_synchronous(struct dax_device *dax_dev) 84 { 85 return true; 86 } 87 static inline void set_dax_synchronous(struct dax_device *dax_dev) 88 { 89 } 90 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 91 struct dax_device *dax_dev) 92 { 93 return !(vma->vm_flags & VM_SYNC); 94 } 95 #endif 96 97 void set_dax_nocache(struct dax_device *dax_dev); 98 void set_dax_nomc(struct dax_device *dax_dev); 99 100 struct writeback_control; 101 #if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) 102 int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk); 103 void dax_remove_host(struct gendisk *disk); 104 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, 105 u64 *start_off); 106 static inline void fs_put_dax(struct dax_device *dax_dev) 107 { 108 put_dax(dax_dev); 109 } 110 #else 111 static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) 112 { 113 return 0; 114 } 115 static inline void dax_remove_host(struct gendisk *disk) 116 { 117 } 118 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, 119 u64 *start_off) 120 { 121 return NULL; 122 } 123 static inline void fs_put_dax(struct dax_device *dax_dev) 124 { 125 } 126 #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */ 127 128 #if IS_ENABLED(CONFIG_FS_DAX) 129 int dax_writeback_mapping_range(struct address_space *mapping, 130 struct dax_device *dax_dev, struct writeback_control *wbc); 131 132 struct page *dax_layout_busy_page(struct address_space *mapping); 133 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); 134 dax_entry_t dax_lock_page(struct page *page); 135 void dax_unlock_page(struct page *page, dax_entry_t cookie); 136 #else 137 static inline struct page *dax_layout_busy_page(struct address_space *mapping) 138 { 139 return NULL; 140 } 141 142 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages) 143 { 144 return NULL; 145 } 146 147 static inline int dax_writeback_mapping_range(struct address_space *mapping, 148 struct dax_device *dax_dev, struct writeback_control *wbc) 149 { 150 return -EOPNOTSUPP; 151 } 152 153 static inline dax_entry_t dax_lock_page(struct page *page) 154 { 155 if (IS_DAX(page->mapping->host)) 156 return ~0UL; 157 return 0; 158 } 159 160 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) 161 { 162 } 163 #endif 164 165 int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, 166 const struct iomap_ops *ops); 167 int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, 168 const struct iomap_ops *ops); 169 170 #if IS_ENABLED(CONFIG_DAX) 171 int dax_read_lock(void); 172 void dax_read_unlock(int id); 173 #else 174 static inline int dax_read_lock(void) 175 { 176 return 0; 177 } 178 179 static inline void dax_read_unlock(int id) 180 { 181 } 182 #endif /* CONFIG_DAX */ 183 bool dax_alive(struct dax_device *dax_dev); 184 void *dax_get_private(struct dax_device *dax_dev); 185 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 186 enum dax_access_mode mode, void **kaddr, pfn_t *pfn); 187 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 188 size_t bytes, struct iov_iter *i); 189 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 190 size_t bytes, struct iov_iter *i); 191 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 192 size_t nr_pages); 193 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); 194 195 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 196 const struct iomap_ops *ops); 197 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 198 pfn_t *pfnp, int *errp, const struct iomap_ops *ops); 199 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 200 enum page_entry_size pe_size, pfn_t pfn); 201 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 202 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 203 pgoff_t index); 204 static inline bool dax_mapping(struct address_space *mapping) 205 { 206 return mapping->host && IS_DAX(mapping->host); 207 } 208 209 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES 210 void hmem_register_device(int target_nid, struct resource *r); 211 #else 212 static inline void hmem_register_device(int target_nid, struct resource *r) 213 { 214 } 215 #endif 216 217 #endif 218