Re: [PATCH 1/4] rbd: move locking out of rbd_header_set_snap()

[Josh Durgin <josh.durgin@inktank.com>]

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

On 09/07/2012 07:50 AM, Alex Elder wrote:
> Move the calls to get the header semaphore out of
> rbd_header_set_snap() and into its caller.
>
> Signed-off-by: Alex Elder <elder@inktank.com>
> ---
>   drivers/block/rbd.c |    5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 634a16c..214c937 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -647,8 +647,6 @@ static int rbd_header_set_snap(struct rbd_device
> *rbd_dev, char *snap_name)
>   {
>   	int ret;
>
> -	down_write(&rbd_dev->header_rwsem);
> -
>   	if (!memcmp(snap_name, RBD_SNAP_HEAD_NAME,
>   		    sizeof (RBD_SNAP_HEAD_NAME))) {
>   		rbd_dev->mapping.snap_id = CEPH_NOSNAP;
> @@ -666,7 +664,6 @@ static int rbd_header_set_snap(struct rbd_device
> *rbd_dev, char *snap_name)
>
>   	ret = 0;
>   done:
> -	up_write(&rbd_dev->header_rwsem);
>   	return ret;
>   }
>
> @@ -2608,7 +2605,9 @@ static ssize_t rbd_add(struct bus_type *bus,
>   	if (rc)
>   		goto err_out_bus;
>
> +	down_write(&rbd_dev->header_rwsem);
>   	rc = rbd_header_set_snap(rbd_dev, snap_name);
> +	up_write(&rbd_dev->header_rwsem);
>   	if (rc)
>   		goto err_out_bus;
>