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 struct iomap_ops;
  11 struct dax_device;
  12 struct dax_operations {
  13         /*
  14          * direct_access: translate a device-relative
  15          * logical-page-offset into an absolute physical pfn. Return the
  16          * number of pages available for DAX at that pfn.
  17          */
  18         long (*direct_access)(struct dax_device *, pgoff_t, long,
  19                         void **, pfn_t *);
  20         /* copy_from_iter: required operation for fs-dax direct-i/o */
  21         size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
  22                         struct iov_iter *);
  23 };
  24
  25 extern struct attribute_group dax_attribute_group;
  26
  27 #if IS_ENABLED(CONFIG_DAX)
  28 struct dax_device *dax_get_by_host(const char *host);
  29 void put_dax(struct dax_device *dax_dev);
  30 #else
  31 static inline struct dax_device *dax_get_by_host(const char *host)
  32 {
  33         return NULL;
  34 }
  35
  36 static inline void put_dax(struct dax_device *dax_dev)
  37 {
  38 }
  39 #endif
  40
  41 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
  42 #if IS_ENABLED(CONFIG_FS_DAX)
  43 int __bdev_dax_supported(struct super_block *sb, int blocksize);
  44 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  45 {
  46         return __bdev_dax_supported(sb, blocksize);
  47 }
  48
  49 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  50 {
  51         return dax_get_by_host(host);
  52 }
  53
  54 static inline void fs_put_dax(struct dax_device *dax_dev)
  55 {
  56         put_dax(dax_dev);
  57 }
  58
  59 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
  60 #else
  61 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  62 {
  63         return -EOPNOTSUPP;
  64 }
  65
  66 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  67 {
  68         return NULL;
  69 }
  70
  71 static inline void fs_put_dax(struct dax_device *dax_dev)
  72 {
  73 }
  74
  75 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
  76 {
  77         return NULL;
  78 }
  79 #endif
  80
  81 int dax_read_lock(void);
  82 void dax_read_unlock(int id);
  83 struct dax_device *alloc_dax(void *private, const char *host,
  84                 const struct dax_operations *ops);
  85 bool dax_alive(struct dax_device *dax_dev);
  86 void kill_dax(struct dax_device *dax_dev);
  87 void *dax_get_private(struct dax_device *dax_dev);
  88 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
  89                 void **kaddr, pfn_t *pfn);
  90 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
  91                 size_t bytes, struct iov_iter *i);
  92 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
  93 void dax_write_cache(struct dax_device *dax_dev, bool wc);
  94 bool dax_write_cache_enabled(struct dax_device *dax_dev);
  95
  96 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
  97                 const struct iomap_ops *ops);
  98 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
  99                     pfn_t *pfnp, const struct iomap_ops *ops);
 100 int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 101                           pfn_t pfn);
 102 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 103 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 104                                       pgoff_t index);
 105
 106 #ifdef CONFIG_FS_DAX
 107 int __dax_zero_page_range(struct block_device *bdev,
 108                 struct dax_device *dax_dev, sector_t sector,
 109                 unsigned int offset, unsigned int length);
 110 #else
 111 static inline int __dax_zero_page_range(struct block_device *bdev,
 112                 struct dax_device *dax_dev, sector_t sector,
 113                 unsigned int offset, unsigned int length)
 114 {
 115         return -ENXIO;
 116 }
 117 #endif
 118
 119 static inline bool dax_mapping(struct address_space *mapping)
 120 {
 121         return mapping->host && IS_DAX(mapping->host);
 122 }
 123
 124 struct writeback_control;
 125 int dax_writeback_mapping_range(struct address_space *mapping,
 126                 struct block_device *bdev, struct writeback_control *wbc);
 127 #endif