gfs2: Replace gfs2_glock_queue_put with gfs2_glock_put_async

Function gfs2_glock_queue_put() puts a glock reference by enqueuing
glock work instead of putting the reference directly.  This ensures that
the operation won't sleep, but it is costly and really only necessary
when putting the final glock reference.  Replace it with a new
gfs2_glock_put_async() function that only queues glock work when putting
the last glock reference.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

1 files changed, 17 insertions, 10 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 34540f9d011c..ed90033b9c72 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -285,14 +285,6 @@ static void __gfs2_glock_put(struct gfs2_glock *gl)
 	sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
 }
 
-/*
- * Cause the glock to be put in work queue context.
- */
-void gfs2_glock_queue_put(struct gfs2_glock *gl)
-{
-	gfs2_glock_queue_work(gl, 0);
-}
-
 /**
  * gfs2_glock_put() - Decrement reference count on glock
  * @gl: The glock to put
@@ -307,6 +299,22 @@ void gfs2_glock_put(struct gfs2_glock *gl)
 	__gfs2_glock_put(gl);
 }
 
+/*
+ * gfs2_glock_put_async - Decrement reference count without sleeping
+ * @gl: The glock to put
+ *
+ * Decrement the reference count on glock immediately unless it is the last
+ * reference.  Defer putting the last reference to work queue context.
+ */
+void gfs2_glock_put_async(struct gfs2_glock *gl)
+{
+	if (lockref_put_or_lock(&gl->gl_lockref))
+		return;
+
+	__gfs2_glock_queue_work(gl, 0);
+	spin_unlock(&gl->gl_lockref.lock);
+}
+
 /**
  * may_grant - check if it's ok to grant a new lock
  * @gl: The glock
@@ -2529,8 +2537,7 @@ static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
 	if (gl) {
 		if (n == 0)
 			return;
-		if (!lockref_put_not_zero(&gl->gl_lockref))
-			gfs2_glock_queue_put(gl);
+		gfs2_glock_put_async(gl);
 	}
 	for (;;) {
 		gl = rhashtable_walk_next(&gi->hti);