Merge with rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git

1 files changed, 6 insertions, 1 deletions

diff --git a/lib/kref.c b/lib/kref.c
index 0d07cc31c81..4a467faf136 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -52,7 +52,12 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref))
 	WARN_ON(release == NULL);
 	WARN_ON(release == (void (*)(struct kref *))kfree);
 
-	if (atomic_dec_and_test(&kref->refcount)) {
+	/*
+	 * if current count is one, we are the last user and can release object
+	 * right now, avoiding an atomic operation on 'refcount'
+	 */
+	if ((atomic_read(&kref->refcount) == 1) ||
+	    (atomic_dec_and_test(&kref->refcount))) {
 		release(kref);
 		return 1;
 	}