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 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 /* zero_page_range: required operation. Zero page range */ 32 int (*zero_page_range)(struct dax_device *, pgoff_t, size_t); 33 }; 34 35 #if IS_ENABLED(CONFIG_DAX) 36 struct dax_device *alloc_dax(void *private, const struct dax_operations *ops); 37 void put_dax(struct dax_device *dax_dev); 38 void kill_dax(struct dax_device *dax_dev); 39 void dax_write_cache(struct dax_device *dax_dev, bool wc); 40 bool dax_write_cache_enabled(struct dax_device *dax_dev); 41 bool dax_synchronous(struct dax_device *dax_dev); 42 void set_dax_synchronous(struct dax_device *dax_dev); 43 /* 44 * Check if given mapping is supported by the file / underlying device. 45 */ 46 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 47 struct dax_device *dax_dev) 48 { 49 if (!(vma->vm_flags & VM_SYNC)) 50 return true; 51 if (!IS_DAX(file_inode(vma->vm_file))) 52 return false; 53 return dax_synchronous(dax_dev); 54 } 55 #else 56 static inline struct dax_device *alloc_dax(void *private, 57 const struct dax_operations *ops) 58 { 59 /* 60 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this 61 * NULL is an error or expected. 62 */ 63 return NULL; 64 } 65 static inline void put_dax(struct dax_device *dax_dev) 66 { 67 } 68 static inline void kill_dax(struct dax_device *dax_dev) 69 { 70 } 71 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc) 72 { 73 } 74 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev) 75 { 76 return false; 77 } 78 static inline bool dax_synchronous(struct dax_device *dax_dev) 79 { 80 return true; 81 } 82 static inline void set_dax_synchronous(struct dax_device *dax_dev) 83 { 84 } 85 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, 86 struct dax_device *dax_dev) 87 { 88 return !(vma->vm_flags & VM_SYNC); 89 } 90 #endif 91 92 void set_dax_nocache(struct dax_device *dax_dev); 93 void set_dax_nomc(struct dax_device *dax_dev); 94 95 struct writeback_control; 96 #if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) 97 int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk); 98 void dax_remove_host(struct gendisk *disk); 99 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, 100 u64 *start_off); 101 static inline void fs_put_dax(struct dax_device *dax_dev) 102 { 103 put_dax(dax_dev); 104 } 105 #else 106 static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) 107 { 108 return 0; 109 } 110 static inline void dax_remove_host(struct gendisk *disk) 111 { 112 } 113 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, 114 u64 *start_off) 115 { 116 return NULL; 117 } 118 static inline void fs_put_dax(struct dax_device *dax_dev) 119 { 120 } 121 #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */ 122 123 #if IS_ENABLED(CONFIG_FS_DAX) 124 int dax_writeback_mapping_range(struct address_space *mapping, 125 struct dax_device *dax_dev, struct writeback_control *wbc); 126 127 struct page *dax_layout_busy_page(struct address_space *mapping); 128 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); 129 dax_entry_t dax_lock_page(struct page *page); 130 void dax_unlock_page(struct page *page, dax_entry_t cookie); 131 #else 132 static inline struct page *dax_layout_busy_page(struct address_space *mapping) 133 { 134 return NULL; 135 } 136 137 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages) 138 { 139 return NULL; 140 } 141 142 static inline int dax_writeback_mapping_range(struct address_space *mapping, 143 struct dax_device *dax_dev, struct writeback_control *wbc) 144 { 145 return -EOPNOTSUPP; 146 } 147 148 static inline dax_entry_t dax_lock_page(struct page *page) 149 { 150 if (IS_DAX(page->mapping->host)) 151 return ~0UL; 152 return 0; 153 } 154 155 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) 156 { 157 } 158 #endif 159 160 int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, 161 const struct iomap_ops *ops); 162 int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, 163 const struct iomap_ops *ops); 164 165 #if IS_ENABLED(CONFIG_DAX) 166 int dax_read_lock(void); 167 void dax_read_unlock(int id); 168 #else 169 static inline int dax_read_lock(void) 170 { 171 return 0; 172 } 173 174 static inline void dax_read_unlock(int id) 175 { 176 } 177 #endif /* CONFIG_DAX */ 178 bool dax_alive(struct dax_device *dax_dev); 179 void *dax_get_private(struct dax_device *dax_dev); 180 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 181 void **kaddr, pfn_t *pfn); 182 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 183 size_t bytes, struct iov_iter *i); 184 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 185 size_t bytes, struct iov_iter *i); 186 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 187 size_t nr_pages); 188 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); 189 190 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 191 const struct iomap_ops *ops); 192 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 193 pfn_t *pfnp, int *errp, const struct iomap_ops *ops); 194 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 195 enum page_entry_size pe_size, pfn_t pfn); 196 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); 197 int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 198 pgoff_t index); 199 static inline bool dax_mapping(struct address_space *mapping) 200 { 201 return mapping->host && IS_DAX(mapping->host); 202 } 203 204 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES 205 void hmem_register_device(int target_nid, struct resource *r); 206 #else 207 static inline void hmem_register_device(int target_nid, struct resource *r) 208 { 209 } 210 #endif 211 212 #endif 213