include/linux/dax.h

   1 #ifndef _LINUX_DAX_H
   2 #define _LINUX_DAX_H
   3
   4 #include <linux/fs.h>
   5 #include <linux/mm.h>
   6 #include <linux/radix-tree.h>
   7 #include <asm/pgtable.h>
   8
   9 struct iomap_ops;
  10 struct dax_device;
  11 struct dax_operations {
  12         /*
  13          * direct_access: translate a device-relative
  14          * logical-page-offset into an absolute physical pfn. Return the
  15          * number of pages available for DAX at that pfn.
  16          */
  17         long (*direct_access)(struct dax_device *, pgoff_t, long,
  18                         void **, pfn_t *);
  19         /* copy_from_iter: required operation for fs-dax direct-i/o */
  20         size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
  21                         struct iov_iter *);
  22 };
  23
  24 extern struct attribute_group dax_attribute_group;
  25
  26 #if IS_ENABLED(CONFIG_DAX)
  27 struct dax_device *dax_get_by_host(const char *host);
  28 void put_dax(struct dax_device *dax_dev);
  29 #else
  30 static inline struct dax_device *dax_get_by_host(const char *host)
  31 {
  32         return NULL;
  33 }
  34
  35 static inline void put_dax(struct dax_device *dax_dev)
  36 {
  37 }
  38 #endif
  39
  40 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
  41 #if IS_ENABLED(CONFIG_FS_DAX)
  42 int __bdev_dax_supported(struct super_block *sb, int blocksize);
  43 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  44 {
  45         return __bdev_dax_supported(sb, blocksize);
  46 }
  47
  48 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  49 {
  50         return dax_get_by_host(host);
  51 }
  52
  53 static inline void fs_put_dax(struct dax_device *dax_dev)
  54 {
  55         put_dax(dax_dev);
  56 }
  57
  58 #else
  59 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  60 {
  61         return -EOPNOTSUPP;
  62 }
  63
  64 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  65 {
  66         return NULL;
  67 }
  68
  69 static inline void fs_put_dax(struct dax_device *dax_dev)
  70 {
  71 }
  72 #endif
  73
  74 int dax_read_lock(void);
  75 void dax_read_unlock(int id);
  76 struct dax_device *alloc_dax(void *private, const char *host,
  77                 const struct dax_operations *ops);
  78 bool dax_alive(struct dax_device *dax_dev);
  79 void kill_dax(struct dax_device *dax_dev);
  80 void *dax_get_private(struct dax_device *dax_dev);
  81 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
  82                 void **kaddr, pfn_t *pfn);
  83 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
  84                 size_t bytes, struct iov_iter *i);
  85 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
  86 void dax_write_cache(struct dax_device *dax_dev, bool wc);
  87 bool dax_write_cache_enabled(struct dax_device *dax_dev);
  88
  89 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
  90                 const struct iomap_ops *ops);
  91 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
  92                     const struct iomap_ops *ops);
  93 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
  94 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
  95                                       pgoff_t index);
  96
  97 #ifdef CONFIG_FS_DAX
  98 int __dax_zero_page_range(struct block_device *bdev,
  99                 struct dax_device *dax_dev, sector_t sector,
 100                 unsigned int offset, unsigned int length);
 101 #else
 102 static inline int __dax_zero_page_range(struct block_device *bdev,
 103                 struct dax_device *dax_dev, sector_t sector,
 104                 unsigned int offset, unsigned int length)
 105 {
 106         return -ENXIO;
 107 }
 108 #endif
 109
 110 static inline bool dax_mapping(struct address_space *mapping)
 111 {
 112         return mapping->host && IS_DAX(mapping->host);
 113 }
 114
 115 struct writeback_control;
 116 int dax_writeback_mapping_range(struct address_space *mapping,
 117                 struct block_device *bdev, struct writeback_control *wbc);
 118 #endif