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 struct dax_device *alloc_dax(void *private, const char *host,
  30                 const struct dax_operations *ops);
  31 void put_dax(struct dax_device *dax_dev);
  32 void kill_dax(struct dax_device *dax_dev);
  33 void dax_write_cache(struct dax_device *dax_dev, bool wc);
  34 bool dax_write_cache_enabled(struct dax_device *dax_dev);
  35 #else
  36 static inline struct dax_device *dax_get_by_host(const char *host)
  37 {
  38         return NULL;
  39 }
  40 static inline struct dax_device *alloc_dax(void *private, const char *host,
  41                 const struct dax_operations *ops)
  42 {
  43         /*
  44          * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
  45          * NULL is an error or expected.
  46          */
  47         return NULL;
  48 }
  49 static inline void put_dax(struct dax_device *dax_dev)
  50 {
  51 }
  52 static inline void kill_dax(struct dax_device *dax_dev)
  53 {
  54 }
  55 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
  56 {
  57 }
  58 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
  59 {
  60         return false;
  61 }
  62 #endif
  63
  64 struct writeback_control;
  65 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
  66 #if IS_ENABLED(CONFIG_FS_DAX)
  67 int __bdev_dax_supported(struct super_block *sb, int blocksize);
  68 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  69 {
  70         return __bdev_dax_supported(sb, blocksize);
  71 }
  72
  73 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  74 {
  75         return dax_get_by_host(host);
  76 }
  77
  78 static inline void fs_put_dax(struct dax_device *dax_dev)
  79 {
  80         put_dax(dax_dev);
  81 }
  82
  83 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
  84 int dax_writeback_mapping_range(struct address_space *mapping,
  85                 struct block_device *bdev, struct writeback_control *wbc);
  86 #else
  87 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  88 {
  89         return -EOPNOTSUPP;
  90 }
  91
  92 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  93 {
  94         return NULL;
  95 }
  96
  97 static inline void fs_put_dax(struct dax_device *dax_dev)
  98 {
  99 }
 100
 101 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 102 {
 103         return NULL;
 104 }
 105
 106 static inline int dax_writeback_mapping_range(struct address_space *mapping,
 107                 struct block_device *bdev, struct writeback_control *wbc)
 108 {
 109         return -EOPNOTSUPP;
 110 }
 111 #endif
 112
 113 int dax_read_lock(void);
 114 void dax_read_unlock(int id);
 115 bool dax_alive(struct dax_device *dax_dev);
 116 void *dax_get_private(struct dax_device *dax_dev);
 117 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 118                 void **kaddr, pfn_t *pfn);
 119 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 120                 size_t bytes, struct iov_iter *i);
 121 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 122
 123 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 124                 const struct iomap_ops *ops);
 125 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 126                     pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
 127 int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 128                           pfn_t pfn);
 129 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 130 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 131                                       pgoff_t index);
 132
 133 #ifdef CONFIG_FS_DAX
 134 int __dax_zero_page_range(struct block_device *bdev,
 135                 struct dax_device *dax_dev, sector_t sector,
 136                 unsigned int offset, unsigned int length);
 137 #else
 138 static inline int __dax_zero_page_range(struct block_device *bdev,
 139                 struct dax_device *dax_dev, sector_t sector,
 140                 unsigned int offset, unsigned int length)
 141 {
 142         return -ENXIO;
 143 }
 144 #endif
 145
 146 static inline bool dax_mapping(struct address_space *mapping)
 147 {
 148         return mapping->host && IS_DAX(mapping->host);
 149 }
 150
 151 #endif