rbd: move locking out of rbd_header_set_snap()

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

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 634a16c40291..214c937a6de5 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;