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: 9f99373790 ("blk-mq: unify hctx delayed_run_work and run_work")
Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jens Axboe 2017-05-03 11:08:14 -06:00
parent 6f63503c8a
commit 2719aa217e

View File

@ -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);