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 dax_device; 15 struct gendisk; 16 struct iomap_ops; 17 struct iomap_iter; 18 struct iomap; 19 20 struct dax_operations { 21 /* 22 * direct_access: translate a device-relative 23 * logical-page-offset into an absolute physical pfn. Return the 24 * number of pages available for DAX at that pfn. 25 */ 26 long (*direct_access)(struct dax_device *, pgoff_t, long, 27 void **, pfn_t *); 28 /* 29 * Validate whether this device is usable as an fsdax backing 30 * device. 31 */ 32 bool (*dax_supported)(struct dax_device *, struct block_device *, int, 33 sector_t, sector_t); 34 /* copy_from_iter: required operation for fs-dax direct-i/o */ 35 size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t, 36 struct iov_iter *); 37 /* copy_to_iter: required operation for fs-dax direct-i/o */ 38 size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t, 39 struct iov_iter *); 40 /* zero_page_range: required operation. Zero page range */ 41 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t); 42 }; 43 44 #if IS_ENABLED(CONFIG_DAX) 45 struct dax_device *alloc_dax(void *private, const struct dax_operations *ops, 46 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 /* 62 * Check if given mapping is supported by the file / underlying device. 63 */ 64 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 65 struct dax_device *dax_dev) 66 { 67 if (!(vma->vm_flags & VM_SYNC)) 68 return true; 69 if (!IS_DAX(file_inode(vma->vm_file))) 70 return false; 71 return dax_synchronous(dax_dev); 72 } 73 #else 74 static inline struct dax_device *alloc_dax(void *private, 75 const struct dax_operations *ops, unsigned long flags) 76 { 77 /* 78 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this 79 * NULL is an error or expected. 80 */ 81 return NULL; 82 } 83 static inline void put_dax(struct dax_device *dax_dev) 84 { 85 } 86 static inline void kill_dax(struct dax_device *dax_dev) 87 { 88 } 89 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc) 90 { 91 } 92 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) 93 { 94 return false; 95 } 96 static inline bool dax_synchronous(struct dax_device *dax_dev) 97 { 98 return true; 99 } 100 static inline void set_dax_synchronous(struct dax_device *dax_dev) 101 { 102 } 103 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 104 struct dax_device *dax_dev) 105 { 106 return !(vma->vm_flags & VM_SYNC); 107 } 108 #endif 109 110 struct writeback_control; 111 #if IS_ENABLED(CONFIG_FS_DAX) 112 int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk); 113 void dax_remove_host(struct gendisk *disk); 114 115 static inline void fs_put_dax(struct dax_device *dax_dev) 116 { 117 put_dax(dax_dev); 118 } 119 120 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); 121 int dax_writeback_mapping_range(struct address_space *mapping, 122 struct dax_device *dax_dev, struct writeback_control *wbc); 123 124 struct page *dax_layout_busy_page(struct address_space *mapping); 125 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); 126 dax_entry_t dax_lock_page(struct page *page); 127 void dax_unlock_page(struct page *page, dax_entry_t cookie); 128 #else 129 static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) 130 { 131 return 0; 132 } 133 static inline void dax_remove_host(struct gendisk *disk) 134 { 135 } 136 137 static inline void fs_put_dax(struct dax_device *dax_dev) 138 { 139 } 140 141 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 142 { 143 return NULL; 144 } 145 146 static inline struct page *dax_layout_busy_page(struct address_space *mapping) 147 { 148 return NULL; 149 } 150 151 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages) 152 { 153 return NULL; 154 } 155 156 static inline int dax_writeback_mapping_range(struct address_space *mapping, 157 struct dax_device *dax_dev, struct writeback_control *wbc) 158 { 159 return -EOPNOTSUPP; 160 } 161 162 static inline dax_entry_t dax_lock_page(struct page *page) 163 { 164 if (IS_DAX(page->mapping->host)) 165 return ~0UL; 166 return 0; 167 } 168 169 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) 170 { 171 } 172 #endif 173 174 int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, 175 const struct iomap_ops *ops); 176 int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, 177 const struct iomap_ops *ops); 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 static inline bool dax_mapping(struct address_space *mapping) 214 { 215 return mapping->host && IS_DAX(mapping->host); 216 } 217 218 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES 219 void hmem_register_device(int target_nid, struct resource *r); 220 #else 221 static inline void hmem_register_device(int target_nid, struct resource *r) 222 { 223 } 224 #endif 225 226 #endif 227