Messages in this thread Patch in this message | | | From | zhengbin <> | Subject | [PATCH] blk-mq: fix a hung issue when set device state to blocked and restore running | Date | Wed, 20 Mar 2019 16:02:01 +0800 |
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When I use dd test a SCSI device which use blk-mq in the following steps: 1.echo "blocked" >/sys/block/sda/device/state 2.dd if=/dev/sda of=/mnt/t.log bs=1M count=10 3.echo "running" >/sys/block/sda/device/state dd should finish this work after step 3, unfortunately, still hung.
After step2, the key code process is like this: blk_mq_dispatch_rq_list-->scsi_queue_rq-->prep_to_mq -->if ret is BLK_STS_RESOURCE, delay run hw queue
prep_to_mq will return BLK_STS_RESOURCE, and scsi_queue_rq will transter it to BLK_STS_DEV_RESOURCE. In this situtation, we should delay run hw queue. This patch fixes that.
Fixes: 86ff7c2a80cd ("blk-mq: introduce BLK_STS_DEV_RESOURCE") Signed-off-by: zhengbin <zhengbin13@huawei.com> --- block/blk-mq.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index a9c1816..556d606 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1309,15 +1309,17 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq * and dm-rq. * - * If driver returns BLK_STS_RESOURCE and SCHED_RESTART - * bit is set, run queue after a delay to avoid IO stalls - * that could otherwise occur if the queue is idle. + * If driver returns BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE + * and SCHED_RESTART bit is set, run queue after a delay to + * avoid IO stalls that could otherwise occur if the queue + * is idle. */ needs_restart = blk_mq_sched_needs_restart(hctx); if (!needs_restart || (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) blk_mq_run_hw_queue(hctx, true); - else if (needs_restart && (ret == BLK_STS_RESOURCE)) + else if (needs_restart && ((ret == BLK_STS_RESOURCE) || + (ret == BLK_STS_DEV_RESOURCE))) blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
blk_mq_update_dispatch_busy(hctx, true); -- 2.7.4
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