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Commit 2719aa21 authored by Jens Axboe's avatar Jens Axboe
Browse files

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: 9f993737 ("blk-mq: unify hctx delayed_run_work and run_work")
Reviewed-by: default avatarBart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 6f63503c

block/blk-mq.c

+20 −5
Original line number Diff line number Diff line
@@ -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);



void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)

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)

{

	__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);