[Cluster-devel] [PATCH dlm/next 2/3] fs: dlm: use kref_put_lock in put_rsb

[Alexander Aring <aahringo@redhat.com>]

This patch will optimize put_rsb() by using kref_put_lock(). The
function kref_put_lock() will only held the lock if the reference is
going to be zero, if not the lock will never be hold.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lock.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 97ca728dc194..a331210434b2 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -350,10 +350,12 @@ static void put_rsb(struct dlm_rsb *r)
 {
 	struct dlm_ls *ls = r->res_ls;
 	uint32_t bucket = r->res_bucket;
+	int rv;
 
-	spin_lock(&ls->ls_rsbtbl[bucket].lock);
-	kref_put(&r->res_ref, toss_rsb);
-	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
+	rv = kref_put_lock(&r->res_ref, toss_rsb,
+			   &ls->ls_rsbtbl[bucket].lock);
+	if (rv)
+		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
 }
 
 void dlm_put_rsb(struct dlm_rsb *r)
-- 
2.31.1