From: Keith Busch <keith.busch@intel.com>
Date: Thu, 8 Jan 2015 01:55:44 +0000 (-0700)
Subject: blk-mq: Let drivers cancel requeue_work
X-Git-Tag: firefly_0821_release~176^2~2521^2~9
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c68ed59f534c318716c6189050af3c5ea03b8071;p=firefly-linux-kernel-4.4.55.git

blk-mq: Let drivers cancel requeue_work

Kicking requeued requests will start h/w queues in a work_queue, which
may alter the driver's requested state to temporarily stop them. This
patch exports a method to cancel the q->requeue_work so a driver can be
assured stopped h/w queues won't be started up before it is ready.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/block/blk-mq.c b/block/blk-mq.c
index ce4811667d36..e73a5dd89fc4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -527,6 +527,12 @@ void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
 }
 EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
 
+void blk_mq_cancel_requeue_work(struct request_queue *q)
+{
+	cancel_work_sync(&q->requeue_work);
+}
+EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work);
+
 void blk_mq_kick_requeue_list(struct request_queue *q)
 {
 	kblockd_schedule_work(&q->requeue_work);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index addf8a19d806..18684e0bdb8a 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -201,6 +201,7 @@ void __blk_mq_end_request(struct request *rq, int error);
 
 void blk_mq_requeue_request(struct request *rq);
 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head);
+void blk_mq_cancel_requeue_work(struct request_queue *q);
 void blk_mq_kick_requeue_list(struct request_queue *q);
 void blk_mq_complete_request(struct request *rq);