include/linux/dax.h

   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 *dax_get_by_host(const char *host);
  45 struct dax_device *alloc_dax(void *private, const char *host,
  46                 const struct dax_operations *ops, 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 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
  62                 int blocksize, sector_t start, sector_t len);
  63 /*
  64  * Check if given mapping is supported by the file / underlying device.
  65  */
  66 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
  67                                              struct dax_device *dax_dev)
  68 {
  69         if (!(vma->vm_flags & VM_SYNC))
  70                 return true;
  71         if (!IS_DAX(file_inode(vma->vm_file)))
  72                 return false;
  73         return dax_synchronous(dax_dev);
  74 }
  75 #else
  76 static inline struct dax_device *dax_get_by_host(const char *host)
  77 {
  78         return NULL;
  79 }
  80 static inline struct dax_device *alloc_dax(void *private, const char *host,
  81                 const struct dax_operations *ops, unsigned long flags)
  82 {
  83         /*
  84          * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
  85          * NULL is an error or expected.
  86          */
  87         return NULL;
  88 }
  89 static inline void put_dax(struct dax_device *dax_dev)
  90 {
  91 }
  92 static inline void kill_dax(struct dax_device *dax_dev)
  93 {
  94 }
  95 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
  96 {
  97 }
  98 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
  99 {
 100         return false;
 101 }
 102 static inline bool dax_synchronous(struct dax_device *dax_dev)
 103 {
 104         return true;
 105 }
 106 static inline void set_dax_synchronous(struct dax_device *dax_dev)
 107 {
 108 }
 109 static inline bool dax_supported(struct dax_device *dax_dev,
 110                 struct block_device *bdev, int blocksize, sector_t start,
 111                 sector_t len)
 112 {
 113         return false;
 114 }
 115 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
 116                                 struct dax_device *dax_dev)
 117 {
 118         return !(vma->vm_flags & VM_SYNC);
 119 }
 120 #endif
 121
 122 struct writeback_control;
 123 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
 124 #if IS_ENABLED(CONFIG_FS_DAX)
 125 bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
 126 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
 127 {
 128         return __bdev_dax_supported(bdev, blocksize);
 129 }
 130
 131 bool __generic_fsdax_supported(struct dax_device *dax_dev,
 132                 struct block_device *bdev, int blocksize, sector_t start,
 133                 sector_t sectors);
 134 static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
 135                 struct block_device *bdev, int blocksize, sector_t start,
 136                 sector_t sectors)
 137 {
 138         return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
 139                         sectors);
 140 }
 141
 142 static inline void fs_put_dax(struct dax_device *dax_dev)
 143 {
 144         put_dax(dax_dev);
 145 }
 146
 147 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
 148 int dax_writeback_mapping_range(struct address_space *mapping,
 149                 struct dax_device *dax_dev, struct writeback_control *wbc);
 150
 151 struct page *dax_layout_busy_page(struct address_space *mapping);
 152 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
 153 dax_entry_t dax_lock_page(struct page *page);
 154 void dax_unlock_page(struct page *page, dax_entry_t cookie);
 155 #else
 156 static inline bool bdev_dax_supported(struct block_device *bdev,
 157                 int blocksize)
 158 {
 159         return false;
 160 }
 161
 162 static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
 163                 struct block_device *bdev, int blocksize, sector_t start,
 164                 sector_t sectors)
 165 {
 166         return false;
 167 }
 168
 169 static inline void fs_put_dax(struct dax_device *dax_dev)
 170 {
 171 }
 172
 173 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 174 {
 175         return NULL;
 176 }
 177
 178 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
 179 {
 180         return NULL;
 181 }
 182
 183 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
 184 {
 185         return NULL;
 186 }
 187
 188 static inline int dax_writeback_mapping_range(struct address_space *mapping,
 189                 struct dax_device *dax_dev, struct writeback_control *wbc)
 190 {
 191         return -EOPNOTSUPP;
 192 }
 193
 194 static inline dax_entry_t dax_lock_page(struct page *page)
 195 {
 196         if (IS_DAX(page->mapping->host))
 197                 return ~0UL;
 198         return 0;
 199 }
 200
 201 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
 202 {
 203 }
 204 #endif
 205
 206 #if IS_ENABLED(CONFIG_DAX)
 207 int dax_read_lock(void);
 208 void dax_read_unlock(int id);
 209 #else
 210 static inline int dax_read_lock(void)
 211 {
 212         return 0;
 213 }
 214
 215 static inline void dax_read_unlock(int id)
 216 {
 217 }
 218 #endif /* CONFIG_DAX */
 219 bool dax_alive(struct dax_device *dax_dev);
 220 void *dax_get_private(struct dax_device *dax_dev);
 221 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 222                 void **kaddr, pfn_t *pfn);
 223 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 224                 size_t bytes, struct iov_iter *i);
 225 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 226                 size_t bytes, struct iov_iter *i);
 227 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 228                         size_t nr_pages);
 229 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 230
 231 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 232                 const struct iomap_ops *ops);
 233 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 234                     pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
 235 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
 236                 enum page_entry_size pe_size, pfn_t pfn);
 237 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 238 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 239                                       pgoff_t index);
 240 s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap);
 241 static inline bool dax_mapping(struct address_space *mapping)
 242 {
 243         return mapping->host && IS_DAX(mapping->host);
 244 }
 245
 246 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES
 247 void hmem_register_device(int target_nid, struct resource *r);
 248 #else
 249 static inline void hmem_register_device(int target_nid, struct resource *r)
 250 {
 251 }
 252 #endif
 253
 254 #endif