2017-08-30 19:43:52

by Dan Williams

[permalink] [raw]
Subject: [PATCH v3 1/4] dax: introduce a fs_dax_get_by_bdev() helper

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.

Cc: Jan Kara <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
---
drivers/dax/super.c | 10 ++++++++++
include/linux/dax.h | 6 ++++++
2 files changed, 16 insertions(+)

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 938eb4868f7f..b699aac268a6 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -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
diff --git a/include/linux/dax.h b/include/linux/dax.h
index df97b7af7e2c..ac8afa18f707 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -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);


2017-08-30 21:40:06

by Darrick J. Wong

[permalink] [raw]
Subject: Re: [PATCH v3 1/4] dax: introduce a fs_dax_get_by_bdev() helper

On Wed, Aug 30, 2017 at 12:43:52PM -0700, Dan Williams wrote:
> 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.
>
> Cc: Jan Kara <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Signed-off-by: Dan Williams <[email protected]>

Reviewed-by: Darrick J. Wong <[email protected]>

> ---
> drivers/dax/super.c | 10 ++++++++++
> include/linux/dax.h | 6 ++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index 938eb4868f7f..b699aac268a6 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -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
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index df97b7af7e2c..ac8afa18f707 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -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);
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html

2017-08-31 08:25:15

by Jan Kara

[permalink] [raw]
Subject: Re: [PATCH v3 1/4] dax: introduce a fs_dax_get_by_bdev() helper

On Wed 30-08-17 12:43:52, Dan Williams wrote:
> 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.
>
> Cc: Jan Kara <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Signed-off-by: Dan Williams <[email protected]>

Looks good to me. You can add:

Reviewed-by: Jan Kara <[email protected]>

Honza
--
Jan Kara <jack-IBi9RG/[email protected]>
SUSE Labs, CR

2017-08-31 09:55:42

by Christoph Hellwig

[permalink] [raw]