From 2719aa217e0d025dbfce74ac777815776ccec072 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 3 May 2017 11:08:14 -0600 Subject: [PATCH] blk-mq: don't use sync workqueue flushing from drivers A previous commit introduced the sync flush, which we need from internal callers like blk_mq_quiesce_queue(). However, we also call the stop helpers from drivers, particularly from ->queue_rq() when we have to stop processing for a bit. We can't block from those locations, and we don't have to guarantee that we're fully flushed. Fixes: 9f993737906b ("blk-mq: unify hctx delayed_run_work and run_work") Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe --- block/blk-mq.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index e339247a2570..dec70ca0aafd 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -41,6 +41,7 @@ static LIST_HEAD(all_q_list); static void blk_mq_poll_stats_start(struct request_queue *q); static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); +static void __blk_mq_stop_hw_queues(struct request_queue *q, bool sync); static int blk_mq_poll_stats_bkt(const struct request *rq) { @@ -166,7 +167,7 @@ void blk_mq_quiesce_queue(struct request_queue *q) unsigned int i; bool rcu = false; - blk_mq_stop_hw_queues(q); + __blk_mq_stop_hw_queues(q, true); queue_for_each_hw_ctx(q, hctx, i) { if (hctx->flags & BLK_MQ_F_BLOCKING) @@ -1218,20 +1219,34 @@ bool blk_mq_queue_stopped(struct request_queue *q) } EXPORT_SYMBOL(blk_mq_queue_stopped); +static void __blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx, bool sync) +{ + if (sync) + cancel_delayed_work_sync(&hctx->run_work); + else + cancel_delayed_work(&hctx->run_work); + + set_bit(BLK_MQ_S_STOPPED, &hctx->state); +} + void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) { - cancel_delayed_work_sync(&hctx->run_work); - set_bit(BLK_MQ_S_STOPPED, &hctx->state); + __blk_mq_stop_hw_queue(hctx, false); } EXPORT_SYMBOL(blk_mq_stop_hw_queue); -void blk_mq_stop_hw_queues(struct request_queue *q) +void __blk_mq_stop_hw_queues(struct request_queue *q, bool sync) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) - blk_mq_stop_hw_queue(hctx); + __blk_mq_stop_hw_queue(hctx, sync); +} + +void blk_mq_stop_hw_queues(struct request_queue *q) +{ + __blk_mq_stop_hw_queues(q, false); } EXPORT_SYMBOL(blk_mq_stop_hw_queues);