blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended delays

BugLink: http://bugs.launchpad.net/bugs/1759723
Make sure that calling blk_mq_run_hw_queue() or
blk_mq_kick_requeue_list() triggers a queue run without delay even
if blk_mq_delay_run_hw_queue() has been called recently and if its
delay has not yet expired.

Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit ae943d20624de0a6aac7dd0597616dce2c498029)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index cd409593ab1978efd04e61a667cf1fcb448201e7..8694a4e4f490e714742f8a7a18da7a10251ea488 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -731,7 +731,7 @@ EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
 
 void blk_mq_kick_requeue_list(struct request_queue *q)
 {
-       kblockd_schedule_delayed_work(&q->requeue_work, 0);
+       kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
 }
 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
 
@@ -1320,9 +1320,8 @@ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
                put_cpu();
        }
 
-       kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
-                                        &hctx->run_work,
-                                        msecs_to_jiffies(msecs));
+       kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
+                                   msecs_to_jiffies(msecs));
 }
 
 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)