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 #include <asm/pgtable.h>
   9
  10 /* Flag for synchronous flush */
  11 #define DAXDEV_F_SYNC (1UL << 0)
  12
  13 typedef unsigned long dax_entry_t;
  14
  15 struct iomap_ops;
  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 };
  38
  39 extern struct attribute_group dax_attribute_group;
  40
  41 #if IS_ENABLED(CONFIG_DAX)
  42 struct dax_device *dax_get_by_host(const char *host);
  43 struct dax_device *alloc_dax(void *private, const char *host,
  44                 const struct dax_operations *ops, unsigned long flags);
  45 void put_dax(struct dax_device *dax_dev);
  46 void kill_dax(struct dax_device *dax_dev);
  47 void dax_write_cache(struct dax_device *dax_dev, bool wc);
  48 bool dax_write_cache_enabled(struct dax_device *dax_dev);
  49 bool __dax_synchronous(struct dax_device *dax_dev);
  50 static inline bool dax_synchronous(struct dax_device *dax_dev)
  51 {
  52         return  __dax_synchronous(dax_dev);
  53 }
  54 void __set_dax_synchronous(struct dax_device *dax_dev);
  55 static inline void set_dax_synchronous(struct dax_device *dax_dev)
  56 {
  57         __set_dax_synchronous(dax_dev);
  58 }
  59 /*
  60  * Check if given mapping is supported by the file / underlying device.
  61  */
  62 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
  63                                              struct dax_device *dax_dev)
  64 {
  65         if (!(vma->vm_flags & VM_SYNC))
  66                 return true;
  67         if (!IS_DAX(file_inode(vma->vm_file)))
  68                 return false;
  69         return dax_synchronous(dax_dev);
  70 }
  71 #else
  72 static inline struct dax_device *dax_get_by_host(const char *host)
  73 {
  74         return NULL;
  75 }
  76 static inline struct dax_device *alloc_dax(void *private, const char *host,
  77                 const struct dax_operations *ops, unsigned long flags)
  78 {
  79         /*
  80          * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
  81          * NULL is an error or expected.
  82          */
  83         return NULL;
  84 }
  85 static inline void put_dax(struct dax_device *dax_dev)
  86 {
  87 }
  88 static inline void kill_dax(struct dax_device *dax_dev)
  89 {
  90 }
  91 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
  92 {
  93 }
  94 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
  95 {
  96         return false;
  97 }
  98 static inline bool dax_synchronous(struct dax_device *dax_dev)
  99 {
 100         return true;
 101 }
 102 static inline void set_dax_synchronous(struct dax_device *dax_dev)
 103 {
 104 }
 105 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
 106                                 struct dax_device *dax_dev)
 107 {
 108         return !(vma->vm_flags & VM_SYNC);
 109 }
 110 #endif
 111
 112 struct writeback_control;
 113 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
 114 #if IS_ENABLED(CONFIG_FS_DAX)
 115 bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
 116 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
 117 {
 118         return __bdev_dax_supported(bdev, blocksize);
 119 }
 120
 121 bool __generic_fsdax_supported(struct dax_device *dax_dev,
 122                 struct block_device *bdev, int blocksize, sector_t start,
 123                 sector_t sectors);
 124 static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
 125                 struct block_device *bdev, int blocksize, sector_t start,
 126                 sector_t sectors)
 127 {
 128         return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
 129                         sectors);
 130 }
 131
 132 static inline void fs_put_dax(struct dax_device *dax_dev)
 133 {
 134         put_dax(dax_dev);
 135 }
 136
 137 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
 138 int dax_writeback_mapping_range(struct address_space *mapping,
 139                 struct dax_device *dax_dev, struct writeback_control *wbc);
 140
 141 struct page *dax_layout_busy_page(struct address_space *mapping);
 142 dax_entry_t dax_lock_page(struct page *page);
 143 void dax_unlock_page(struct page *page, dax_entry_t cookie);
 144 #else
 145 static inline bool bdev_dax_supported(struct block_device *bdev,
 146                 int blocksize)
 147 {
 148         return false;
 149 }
 150
 151 static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
 152                 struct block_device *bdev, int blocksize, sector_t start,
 153                 sector_t sectors)
 154 {
 155         return false;
 156 }
 157
 158 static inline void fs_put_dax(struct dax_device *dax_dev)
 159 {
 160 }
 161
 162 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 163 {
 164         return NULL;
 165 }
 166
 167 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
 168 {
 169         return NULL;
 170 }
 171
 172 static inline int dax_writeback_mapping_range(struct address_space *mapping,
 173                 struct dax_device *dax_dev, struct writeback_control *wbc)
 174 {
 175         return -EOPNOTSUPP;
 176 }
 177
 178 static inline dax_entry_t dax_lock_page(struct page *page)
 179 {
 180         if (IS_DAX(page->mapping->host))
 181                 return ~0UL;
 182         return 0;
 183 }
 184
 185 static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
 186 {
 187 }
 188 #endif
 189
 190 int dax_read_lock(void);
 191 void dax_read_unlock(int id);
 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 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
 197                 int blocksize, sector_t start, sector_t len);
 198 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 199                 size_t bytes, struct iov_iter *i);
 200 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 201                 size_t bytes, struct iov_iter *i);
 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
 214 #ifdef CONFIG_FS_DAX
 215 int __dax_zero_page_range(struct block_device *bdev,
 216                 struct dax_device *dax_dev, sector_t sector,
 217                 unsigned int offset, unsigned int length);
 218 #else
 219 static inline int __dax_zero_page_range(struct block_device *bdev,
 220                 struct dax_device *dax_dev, sector_t sector,
 221                 unsigned int offset, unsigned int length)
 222 {
 223         return -ENXIO;
 224 }
 225 #endif
 226
 227 static inline bool dax_mapping(struct address_space *mapping)
 228 {
 229         return mapping->host && IS_DAX(mapping->host);
 230 }
 231
 232 #endif