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         /* copy_to_iter: required operation for fs-dax direct-i/o */
  24         size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t,
  25                         struct iov_iter *);
  26 };
  27
  28 extern struct attribute_group dax_attribute_group;
  29
  30 #if IS_ENABLED(CONFIG_DAX)
  31 struct dax_device *dax_get_by_host(const char *host);
  32 struct dax_device *alloc_dax(void *private, const char *host,
  33                 const struct dax_operations *ops);
  34 void put_dax(struct dax_device *dax_dev);
  35 void kill_dax(struct dax_device *dax_dev);
  36 void dax_write_cache(struct dax_device *dax_dev, bool wc);
  37 bool dax_write_cache_enabled(struct dax_device *dax_dev);
  38 #else
  39 static inline struct dax_device *dax_get_by_host(const char *host)
  40 {
  41         return NULL;
  42 }
  43 static inline struct dax_device *alloc_dax(void *private, const char *host,
  44                 const struct dax_operations *ops)
  45 {
  46         /*
  47          * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
  48          * NULL is an error or expected.
  49          */
  50         return NULL;
  51 }
  52 static inline void put_dax(struct dax_device *dax_dev)
  53 {
  54 }
  55 static inline void kill_dax(struct dax_device *dax_dev)
  56 {
  57 }
  58 static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
  59 {
  60 }
  61 static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
  62 {
  63         return false;
  64 }
  65 #endif
  66
  67 struct writeback_control;
  68 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
  69 #if IS_ENABLED(CONFIG_FS_DAX)
  70 bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
  71 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
  72 {
  73         return __bdev_dax_supported(bdev, blocksize);
  74 }
  75
  76 static inline struct dax_device *fs_dax_get_by_host(const char *host)
  77 {
  78         return dax_get_by_host(host);
  79 }
  80
  81 static inline void fs_put_dax(struct dax_device *dax_dev)
  82 {
  83         put_dax(dax_dev);
  84 }
  85
  86 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
  87 int dax_writeback_mapping_range(struct address_space *mapping,
  88                 struct block_device *bdev, struct writeback_control *wbc);
  89
  90 struct page *dax_layout_busy_page(struct address_space *mapping);
  91 bool dax_lock_mapping_entry(struct page *page);
  92 void dax_unlock_mapping_entry(struct page *page);
  93 #else
  94 static inline bool bdev_dax_supported(struct block_device *bdev,
  95                 int blocksize)
  96 {
  97         return false;
  98 }
  99
 100 static inline struct dax_device *fs_dax_get_by_host(const char *host)
 101 {
 102         return NULL;
 103 }
 104
 105 static inline void fs_put_dax(struct dax_device *dax_dev)
 106 {
 107 }
 108
 109 static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 110 {
 111         return NULL;
 112 }
 113
 114 static inline struct page *dax_layout_busy_page(struct address_space *mapping)
 115 {
 116         return NULL;
 117 }
 118
 119 static inline int dax_writeback_mapping_range(struct address_space *mapping,
 120                 struct block_device *bdev, struct writeback_control *wbc)
 121 {
 122         return -EOPNOTSUPP;
 123 }
 124
 125 static inline bool dax_lock_mapping_entry(struct page *page)
 126 {
 127         if (IS_DAX(page->mapping->host))
 128                 return true;
 129         return false;
 130 }
 131
 132 static inline void dax_unlock_mapping_entry(struct page *page)
 133 {
 134 }
 135 #endif
 136
 137 int dax_read_lock(void);
 138 void dax_read_unlock(int id);
 139 bool dax_alive(struct dax_device *dax_dev);
 140 void *dax_get_private(struct dax_device *dax_dev);
 141 long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 142                 void **kaddr, pfn_t *pfn);
 143 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 144                 size_t bytes, struct iov_iter *i);
 145 size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 146                 size_t bytes, struct iov_iter *i);
 147 void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 148
 149 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 150                 const struct iomap_ops *ops);
 151 vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 152                     pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
 153 vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
 154                 enum page_entry_size pe_size, pfn_t pfn);
 155 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 156 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 157                                       pgoff_t index);
 158
 159 #ifdef CONFIG_FS_DAX
 160 int __dax_zero_page_range(struct block_device *bdev,
 161                 struct dax_device *dax_dev, sector_t sector,
 162                 unsigned int offset, unsigned int length);
 163 #else
 164 static inline int __dax_zero_page_range(struct block_device *bdev,
 165                 struct dax_device *dax_dev, sector_t sector,
 166                 unsigned int offset, unsigned int length)
 167 {
 168         return -ENXIO;
 169 }
 170 #endif
 171
 172 static inline bool dax_mapping(struct address_space *mapping)
 173 {
 174         return mapping->host && IS_DAX(mapping->host);
 175 }
 176
 177 #endif