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 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         /* zero_page_range: required operation. Zero page range   */
  31         int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
  32         /*
  33          * recovery_write: recover a poisoned range by DAX device driver
  34          * capable of clearing poison.
  35          */
  36         size_t (*recovery_write)(struct dax_device *dax_dev, pgoff_t pgoff,
  37                         void *addr, size_t bytes, struct iov_iter *iter);
  38 };
  39
  40 struct dax_holder_operations {
  41         /*
  42          * notify_failure - notify memory failure into inner holder device
  43          * @dax_dev: the dax device which contains the holder
  44          * @offset: offset on this dax device where memory failure occurs
  45          * @len: length of this memory failure event
  46          * @flags: action flags for memory failure handler
  47          */
  48         int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
  49                         u64 len, int mf_flags);
  50 };
  51
  52 #if IS_ENABLED(CONFIG_DAX)
  53 struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
  54 void *dax_holder(struct dax_device *dax_dev);
  55 void put_dax(struct dax_device *dax_dev);
  56 void kill_dax(struct dax_device *dax_dev);
  57 void dax_write_cache(struct dax_device *dax_dev, bool wc);
  58 bool dax_write_cache_enabled(struct dax_device *dax_dev);
  59 bool dax_synchronous(struct dax_device *dax_dev);
  60 void set_dax_nocache(struct dax_device *dax_dev);
  61 void set_dax_nomc(struct dax_device *dax_dev);
  62 void set_dax_synchronous(struct dax_device *dax_dev);
  63 size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
  64                 void *addr, size_t bytes, struct iov_iter *i);
  65 /*
  66  * Check if given mapping is supported by the file / underlying device.
  67  */
  68 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
  69                                              struct dax_device *dax_dev)
  70 {
  71         if (!(vma->vm_flags & VM_SYNC))
  72                 return true;
  73         if (!IS_DAX(file_inode(vma->vm_file)))
  74                 return false;
  75         return dax_synchronous(dax_dev);
  76 }
  77 #else
  78 static inline void *dax_holder(struct dax_device *dax_dev)
  79 {
  80         return NULL;
  81 }
  82 static inline struct dax_device *alloc_dax(void *private,
  83                 const struct dax_operations *ops)
  84 {
  85         return ERR_PTR(-EOPNOTSUPP);
  86 }
  87 static inline void put_dax(struct dax_device *dax_dev)
  88 {
  89 }
  90 static inline void kill_dax(struct dax_device *dax_dev)
  91 {
  92 }
  93 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
  94 {
  95 }
  96 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
  97 {
  98         return false;
  99 }
 100 static inline bool dax_synchronous(struct dax_device *dax_dev)
 101 {
 102         return true;
 103 }
 104 static inline void set_dax_nocache(struct dax_device *dax_dev)
 105 {
 106 }
 107 static inline void set_dax_nomc(struct dax_device *dax_dev)
 108 {
 109 }
 110 static inline void set_dax_synchronous(struct dax_device *dax_dev)
 111 {
 112 }
 113 static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
 114                                 struct dax_device *dax_dev)
 115 {
 116         return !(vma->vm_flags & VM_SYNC);
 117 }
 118 static inline size_t dax_recovery_write(struct dax_device *dax_dev,
 119                 pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
 120 {
 121         return 0;
 122 }
 123 #endif
 124
 125 struct writeback_control;
 126 #if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
 127 int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
 128 void dax_remove_host(struct gendisk *disk);
 129 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
 130                 void *holder, const struct dax_holder_operations *ops);
 131 void fs_put_dax(struct dax_device *dax_dev, void *holder);
 132 #else
 133 static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk)
 134 {
 135         return 0;
 136 }
 137 static inline void dax_remove_host(struct gendisk *disk)
 138 {
 139 }
 140 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev,
 141                 u64 *start_off, void *holder,
 142                 const struct dax_holder_operations *ops)
 143 {
 144         return NULL;
 145 }
 146 static inline void fs_put_dax(struct dax_device *dax_dev, void *holder)
 147 {
 148 }
 149 #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
 150
 151 #if IS_ENABLED(CONFIG_FS_DAX)
 152 int dax_writeback_mapping_range(struct address_space *mapping,
 153                 struct dax_device *dax_dev, struct writeback_control *wbc);
 154
 155 struct page *dax_layout_busy_page(struct address_space *mapping);
 156 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
 157 dax_entry_t dax_lock_folio(struct folio *folio);
 158 void dax_unlock_folio(struct folio *folio, dax_entry_t cookie);
 159 dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
 160                 unsigned long index, struct page **page);
 161 void dax_unlock_mapping_entry(struct address_space *mapping,
 162                 unsigned long index, dax_entry_t cookie);
 163 #else
 164 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
 165 {
 166         return NULL;
 167 }
 168
 169 static inline struct page *dax_layout_busy_page_range(struct address_space *mapping, pgoff_t start, pgoff_t nr_pages)
 170 {
 171         return NULL;
 172 }
 173
 174 static inline int dax_writeback_mapping_range(struct address_space *mapping,
 175                 struct dax_device *dax_dev, struct writeback_control *wbc)
 176 {
 177         return -EOPNOTSUPP;
 178 }
 179
 180 static inline dax_entry_t dax_lock_folio(struct folio *folio)
 181 {
 182         if (IS_DAX(folio->mapping->host))
 183                 return ~0UL;
 184         return 0;
 185 }
 186
 187 static inline void dax_unlock_folio(struct folio *folio, dax_entry_t cookie)
 188 {
 189 }
 190
 191 static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
 192                 unsigned long index, struct page **page)
 193 {
 194         return 0;
 195 }
 196
 197 static inline void dax_unlock_mapping_entry(struct address_space *mapping,
 198                 unsigned long index, dax_entry_t cookie)
 199 {
 200 }
 201 #endif
 202
 203 int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
 204                 const struct iomap_ops *ops);
 205 int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
 206                 const struct iomap_ops *ops);
 207 int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
 208                 const struct iomap_ops *ops);
 209
 210 #if IS_ENABLED(CONFIG_DAX)
 211 int dax_read_lock(void);
 212 void dax_read_unlock(int id);
 213 #else
 214 static inline int dax_read_lock(void)
 215 {
 216         return 0;
 217 }
 218
 219 static inline void dax_read_unlock(int id)
 220 {
 221 }
 222 #endif /* CONFIG_DAX */
 223 bool dax_alive(struct dax_device *dax_dev);
 224 void *dax_get_private(struct dax_device *dax_dev);
 225 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 226                 enum dax_access_mode mode, void **kaddr, pfn_t *pfn);
 227 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 228                 size_t bytes, struct iov_iter *i);
 229 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 230                 size_t bytes, struct iov_iter *i);
 231 int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 232                         size_t nr_pages);
 233 int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len,
 234                 int mf_flags);
 235 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 236
 237 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 238                 const struct iomap_ops *ops);
 239 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
 240                     pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
 241 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
 242                 unsigned int order, pfn_t pfn);
 243 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 244 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 245                                       pgoff_t index);
 246 int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
 247                                   struct inode *dest, loff_t destoff,
 248                                   loff_t len, bool *is_same,
 249                                   const struct iomap_ops *ops);
 250 int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
 251                               struct file *file_out, loff_t pos_out,
 252                               loff_t *len, unsigned int remap_flags,
 253                               const struct iomap_ops *ops);
 254 static inline bool dax_mapping(struct address_space *mapping)
 255 {
 256         return mapping->host && IS_DAX(mapping->host);
 257 }
 258
 259 /*
 260  * Due to dax's memory and block duo personalities, hwpoison reporting
 261  * takes into consideration which personality is presently visible.
 262  * When dax acts like a block device, such as in block IO, an encounter of
 263  * dax hwpoison is reported as -EIO.
 264  * When dax acts like memory, such as in page fault, a detection of hwpoison
 265  * is reported as -EHWPOISON which leads to VM_FAULT_HWPOISON.
 266  */
 267 static inline int dax_mem2blk_err(int err)
 268 {
 269         return (err == -EHWPOISON) ? -EIO : err;
 270 }
 271
 272 #ifdef CONFIG_DEV_DAX_HMEM_DEVICES
 273 void hmem_register_resource(int target_nid, struct resource *r);
 274 #else
 275 static inline void hmem_register_resource(int target_nid, struct resource *r)
 276 {
 277 }
 278 #endif
 279
 280 typedef int (*walk_hmem_fn)(struct device *dev, int target_nid,
 281                             const struct resource *res);
 282 int walk_hmem_resources(struct device *dev, walk_hmem_fn fn);
 283 #endif