From 818c5f3bef750eb5998b468f84391e4d656b97ed Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Sat, 20 Feb 2016 00:38:47 -0500 Subject: [PATCH] dm: fix a couple locking issues with use of block interfaces old_stop_queue() was checking blk_queue_stopped() without holding the q->queue_lock. dm_requeue_original_request() needed to check blk_queue_stopped(), with q->queue_lock held, before calling blk_mq_kick_requeue_list(). And a side-effect of that change is start_queue() must also call blk_mq_kick_requeue_list(). Signed-off-by: Mike Snitzer --- drivers/md/dm.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e9035959f904..8a62e43fbff5 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1215,6 +1215,18 @@ static void old_requeue_request(struct request *rq) spin_unlock_irqrestore(q->queue_lock, flags); } +static void dm_mq_requeue_request(struct request *rq) +{ + struct request_queue *q = rq->q; + unsigned long flags; + + blk_mq_requeue_request(rq); + spin_lock_irqsave(q->queue_lock, flags); + if (!blk_queue_stopped(q)) + blk_mq_kick_requeue_list(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} + static void dm_requeue_original_request(struct mapped_device *md, struct request *rq) { @@ -1225,10 +1237,8 @@ static void dm_requeue_original_request(struct mapped_device *md, rq_end_stats(md, rq); if (!rq->q->mq_ops) old_requeue_request(rq); - else { - blk_mq_requeue_request(rq); - blk_mq_kick_requeue_list(rq->q); - } + else + dm_mq_requeue_request(rq); rq_completed(md, rw, false); } @@ -1237,10 +1247,12 @@ static void old_stop_queue(struct request_queue *q) { unsigned long flags; - if (blk_queue_stopped(q)) + spin_lock_irqsave(q->queue_lock, flags); + if (blk_queue_stopped(q)) { + spin_unlock_irqrestore(q->queue_lock, flags); return; + } - spin_lock_irqsave(q->queue_lock, flags); blk_stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); } @@ -1267,8 +1279,10 @@ static void start_queue(struct request_queue *q) { if (!q->mq_ops) old_start_queue(q); - else + else { blk_mq_start_stopped_hw_queues(q, true); + blk_mq_kick_requeue_list(q); + } } static void dm_done(struct request *clone, int error, bool mapped) -- 2.20.1