/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _LINUX_DAX_H
  #define _LINUX_DAX_H
  
  #include <linux/fs.h>
  #include <linux/mm.h>

  #include <linux/radix-tree.h>

  #include <asm/pgtable.h>

  struct iomap_ops;

  struct dax_device;
  struct dax_operations {
  	/*
  	 * direct_access: translate a device-relative
  	 * logical-page-offset into an absolute physical pfn. Return the
  	 * number of pages available for DAX at that pfn.
  	 */
  	long (*direct_access)(struct dax_device *, pgoff_t, long,
  			void **, pfn_t *);

  	/* copy_from_iter: required operation for fs-dax direct-i/o */

  	size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
  			struct iov_iter *);

  };

  extern struct attribute_group dax_attribute_group;

  #if IS_ENABLED(CONFIG_DAX)
  struct dax_device *dax_get_by_host(const char *host);
  void put_dax(struct dax_device *dax_dev);
  #else
  static inline struct dax_device *dax_get_by_host(const char *host)
  {
  	return NULL;
  }
  
  static inline void put_dax(struct dax_device *dax_dev)
  {
  }
  #endif

  int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
  #if IS_ENABLED(CONFIG_FS_DAX)

  bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
  static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)

  {

  	return __bdev_dax_supported(bdev, blocksize);

  }

  
  static inline struct dax_device *fs_dax_get_by_host(const char *host)
  {
  	return dax_get_by_host(host);
  }
  
  static inline void fs_put_dax(struct dax_device *dax_dev)
  {
  	put_dax(dax_dev);
  }

  struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev);

  #else

  static inline bool bdev_dax_supported(struct block_device *bdev,

  		int blocksize)

  {

  	return false;

  }

  static inline struct dax_device *fs_dax_get_by_host(const char *host)

  {
  	return NULL;
  }

  static inline void fs_put_dax(struct dax_device *dax_dev)

  {
  }

  
  static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
  {
  	return NULL;
  }

  #endif

  int dax_read_lock(void);
  void dax_read_unlock(int id);

  struct dax_device *alloc_dax(void *private, const char *host,
  		const struct dax_operations *ops);

  bool dax_alive(struct dax_device *dax_dev);
  void kill_dax(struct dax_device *dax_dev);
  void *dax_get_private(struct dax_device *dax_dev);

  long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
  		void **kaddr, pfn_t *pfn);

  size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
  		size_t bytes, struct iov_iter *i);

  void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);

  void dax_write_cache(struct dax_device *dax_dev, bool wc);

  bool dax_write_cache_enabled(struct dax_device *dax_dev);

  ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,

  		const struct iomap_ops *ops);

  int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
  		    const struct iomap_ops *ops);

  int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);

  int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
  				      pgoff_t index);

  
  #ifdef CONFIG_FS_DAX

  int __dax_zero_page_range(struct block_device *bdev,
  		struct dax_device *dax_dev, sector_t sector,

  		unsigned int offset, unsigned int length);

  #else

  static inline int __dax_zero_page_range(struct block_device *bdev,

  		struct dax_device *dax_dev, sector_t sector,
  		unsigned int offset, unsigned int length)

  {
  	return -ENXIO;
  }

  #endif

  static inline bool dax_mapping(struct address_space *mapping)
  {
  	return mapping->host && IS_DAX(mapping->host);
  }

  
  struct writeback_control;
  int dax_writeback_mapping_range(struct address_space *mapping,
  		struct block_device *bdev, struct writeback_control *wbc);

  #endif