[PATCH 02/11] block: relocate elevator initialized test from blk_cleanup_queue() to blk_drain_queue()

[Tejun Heo <tj@kernel.org>]

blk_cleanup_queue() may be called for a queue which doesn't have
elevator initialized to skip invoking blk_drain_queue().
blk_drain_queue() will be used for other purposes too and may be
called for such half-initialized queues from other paths.  Move
q->elevator test into blk_drain_queue().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
---
 block/blk-core.c |   16 +++++++++-------
 1 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 1b73d06..ddda1cc 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -359,6 +359,13 @@ EXPORT_SYMBOL(blk_put_queue);
  */
 void blk_drain_queue(struct request_queue *q, bool drain_all)
 {
+	/*
+	 * The caller might be trying to tear down @q before its elevator
+	 * is initialized, in which case we don't want to call into it.
+	 */
+	if (!q->elevator)
+		return;
+
 	while (true) {
 		bool drain = false;
 		int i;
@@ -468,13 +475,8 @@ void blk_cleanup_queue(struct request_queue *q)
 	spin_unlock_irq(lock);
 	mutex_unlock(&q->sysfs_lock);
 
-	/*
-	 * Drain all requests queued before DEAD marking.  The caller might
-	 * be trying to tear down @q before its elevator is initialized, in
-	 * which case we don't want to call into draining.
-	 */
-	if (q->elevator)
-		blk_drain_queue(q, true);
+	/* drain all requests queued before DEAD marking */
+	blk_drain_queue(q, true);
 
 	/* @q won't process any more request, flush async actions */
 	del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
-- 
1.7.7.3