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  *   ˆl–Ü4ý( ©³( 	Å€fàB¦-ÿ¿ƒyöA_†I|¥+ÄÃ "â    /* 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>

typedef unsigned long dax_entry_t;

struct dax_device;
struct gendisk;
struct iomap_ops;
struct iomap_iter;
struct iomap;

enum dax_access_mode {
	DAX_ACCESS,
	DAX_RECOVERY_WRITE,
};

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,
			enum dax_access_mode, void **, pfn_t *);
	/*
	 * Validate whether this device is usable as an fsdax backing
	 * device.
	 */
	bool (*dax_supported)(struct dax_device *, struct block_device *, int,
			sector_t, sector_t);
	/* zero_page_range: required operation. Zero page range   */
	int (*zero_page_range)(struct dax_device *, pgoff_t, size_t);
	/*
	 * recovery_write: recover a poisoned range by DAX device driver
	 * capable of clearing poison.
	 */
	size_t (*recovery_write)(struct dax_device *dax_dev, pgoff_t pgoff,
			void *addr, size_t bytes, struct iov_iter *iter);
};

struct dax_holder_operations {
	/*
	 * notify_failure - notify memory failure into inner holder device
	 * @dax_dev: the dax device which contains the holder
	 * @offset: offset on this dax device where memory failure occurs
	 * @len: length of this memory failure event
	 * @flags: action flags for memory failure handler
	 */
	int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
			u64 len, int mf_flags);
};

#if IS_ENABLED(CONFIG_DAX)
struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
void *dax_holder(struct dax_device *dax_dev);
void put_dax(struct dax_device *dax_dev);
void kill_dax(struct dax_device *dax_dev);
void dax_write_cache(struct dax_device *dax_dev, bool wc);
bool dax_write_cache_enabled(struct dax_device *dax_dev);
bool dax_synchronous(struct dax_device *dax_dev);
void set_dax_synchronous(struct dax_device *dax_dev);
size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
		void *addr, size_t bytes, struct iov_iter *i);
/*
 * Check if given mapping is supported by the file / underlying device.
 */
static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
					     struct dax_device *dax_dev)
{
	if (!(vma->vm_flags & VM_SYNC))
		return true;
	if (!IS_DAX(file_inode(vma->vm_file)))
		return false;
	return dax_synchronous(dax_dev);
}
#else
static inline void *dax_holder(struct dax_device *dax_dev)
{
	return NULL;
}
static inline struct dax_device *alloc_dax(void *private,
		const struct dax_operations *ops)
{
	/*
	 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
	 * NULL is an error or expected.
	 */
	return NULL;
}
static inline void put_dax(struct dax_device *dax_dev)
{
}
static inline void kill_dax(struct dax_device *dax_dev)
{
}
static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
{
}
static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
{
	return false;
}
static inline bool dax_synchronous(struct dax_device *dax_dev)
{
	return true;
}
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
				struct dax_device *dax_dev)
{
	return !(vma->vm_flags & VM_SYNC);
}
static inline size_t dax_recovery_write(struct dax_device *dax_dev,
		pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
{
	return 0;
}
#endif

void set_dax_nocache(struct dax_device *dax_dev);
void set_dax_nomc(struct dax_device *dax_dev);

struct writeback_control;
#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk);
void dax_remove_host(struct gendisk *disk);
struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off,
		void *holder, const struct dax_holder_operations *ops);
void fs_put_dax(struct dax_device *dax_dev, void *holder);
#el