LXR linux/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
  10struct iomap_ops;
  11struct dax_device;
  12struct 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
  25extern struct attribute_group dax_attribute_group;
  26
  27#if IS_ENABLED(CONFIG_DAX)
  28struct dax_device *dax_get_by_host(const char *host);
  29struct dax_device *alloc_dax(void *private, const char *host,
  30                const struct dax_operations *ops);
  31void put_dax(struct dax_device *dax_dev);
  32void kill_dax(struct dax_device *dax_dev);
  33void dax_write_cache(struct dax_device *dax_dev, bool wc);
  34bool dax_write_cache_enabled(struct dax_device *dax_dev);
  35#else
  36static inline struct dax_device *dax_get_by_host(const char *host)
  37{
  38        return NULL;
  39}
  40static 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}
  49static inline void put_dax(struct dax_device *dax_dev)
  50{
  51}
  52static inline void kill_dax(struct dax_device *dax_dev)
  53{
  54}
  55static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
  56{
  57}
  58static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
  59{
  60        return false;
  61}
  62#endif
  63
  64struct writeback_control;
  65int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
  66#if IS_ENABLED(CONFIG_FS_DAX)
  67int __bdev_dax_supported(struct super_block *sb, int blocksize);
  68static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  69{
  70        return __bdev_dax_supported(sb, blocksize);
  71}
  72
  73static inline struct dax_device *fs_dax_get_by_host(const char *host)
  74{
  75        return dax_get_by_host(host);
  76}
  77
  78static inline void fs_put_dax(struct dax_device *dax_dev)
  79{
  80        put_dax(dax_dev);
  81}
  82
  83struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);
  84int dax_writeback_mapping_range(struct address_space *mapping,
  85                struct block_device *bdev, struct writeback_control *wbc);
  86#else
  87static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
  88{
  89        return -EOPNOTSUPP;
  90}
  91
  92static inline struct dax_device *fs_dax_get_by_host(const char *host)
  93{
  94        return NULL;
  95}
  96
  97static inline void fs_put_dax(struct dax_device *dax_dev)
  98{
  99}
 100
 101static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
 102{
 103        return NULL;
 104}
 105
 106static 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
 113int dax_read_lock(void);
 114void dax_read_unlock(int id);
 115bool dax_alive(struct dax_device *dax_dev);
 116void *dax_get_private(struct dax_device *dax_dev);
 117long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 118                void **kaddr, pfn_t *pfn);
 119size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 120                size_t bytes, struct iov_iter *i);
 121void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 122
 123ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 124                const struct iomap_ops *ops);
 125int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 126                    pfn_t *pfnp, int *errp, const struct iomap_ops *ops);
 127int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 128                          pfn_t pfn);
 129int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 130int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 131                                      pgoff_t index);
 132
 133#ifdef CONFIG_FS_DAX
 134int __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
 138static 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
 146static inline bool dax_mapping(struct address_space *mapping)
 147{
 148        return mapping->host && IS_DAX(mapping->host);
 149}
 150
 151#endif
 152