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dax: introduce a fs_dax_get_by_bdev() helper

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Add a helper that can replace the following common pattern:

	if (blk_queue_dax(bdev->bd_queue))
		fs_dax_get_by_host(bdev->bd_disk->disk_name);

This will be used to move dax_device lookup from iomap-operation time to
fs-mount time.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2017-08-30 09:16:38 -07:00
parent 14ccee78fc
commit 78f3547350
2 changed files with 16 additions and 0 deletions
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10
drivers/dax/super.c
View file

@ -46,6 +46,8 @@ void dax_read_unlock(int id)
EXPORT_SYMBOL_GPL(dax_read_unlock);
#ifdef CONFIG_BLOCK
#include <linux/blkdev.h>
int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
pgoff_t *pgoff)
{
@ -59,6 +61,14 @@ int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
}
EXPORT_SYMBOL(bdev_dax_pgoff);
struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
{
if (!blk_queue_dax(bdev->bd_queue))
return NULL;
return fs_dax_get_by_host(bdev->bd_disk->disk_name);
}
EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
/**
* __bdev_dax_supported() - Check if the device supports dax for filesystem
* @sb: The superblock of the device

6
include/linux/dax.h
View file

@ -57,6 +57,7 @@ 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 int bdev_dax_supported(struct super_block *sb, int blocksize)
{
@ -71,6 +72,11 @@ static inline struct dax_device *fs_dax_get_by_host(const char *host)
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);