gfs2: Get rid of unnecessary test_and_set_bit

The GLF_LOCK flag is protected by the gl->gl_lockref.lock spin lock
which is held when entering run_queue(), so we can use test_bit() and
set_bit() here.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/glock.c

@@ -842,8 +842,9 @@ __acquires(&gl->gl_lockref.lock)
 {
 	struct gfs2_holder *gh = NULL;
 
-	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
+	if (test_bit(GLF_LOCK, &gl->gl_flags))
 		return;
+	set_bit(GLF_LOCK, &gl->gl_flags);
 
 	GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));