From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "hch@infradead.org" <hch@infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>,
"ming.lei@redhat.com" <ming.lei@redhat.com>
Cc: "dm-devel@redhat.com" <dm-devel@redhat.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH v3 3/9] blk-mq: use the introduced blk_mq_unquiesce_queue()
Date: Wed, 31 May 2017 15:21:41 +0000 [thread overview]
Message-ID: <1496244100.2608.3.camel@sandisk.com> (raw)
In-Reply-To: <20170531123706.20885-4-ming.lei@redhat.com>
On Wed, 2017-05-31 at 20:37 +0800, Ming Lei wrote:
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 99e16ac479e3..ffcf05765e2b 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -3031,7 +3031,10 @@ scsi_internal_device_unblock(struct scsi_device *sdev,
> return -EINVAL;
>
> if (q->mq_ops) {
> - blk_mq_start_stopped_hw_queues(q, false);
> + if (blk_queue_quiesced(q))
> + blk_mq_unquiesce_queue(q);
> + else
> + blk_mq_start_stopped_hw_queues(q, false);
> } else {
> spin_lock_irqsave(q->queue_lock, flags);
> blk_start_queue(q);
As I commented on v2, this change is really wrong. All what's needed here is
a call to blk_mq_unquiesce_queue() and nothing else. Adding a call to
blk_mq_start_stopped_hw_queues() is wrong because it makes it impossible to
use the STOPPED flag in the SCSI core to make the block layer core stop calling
.queue_rq() if a SCSI LLD returns "busy".
Bart.
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next prev parent reply other threads:[~2017-05-31 15:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-31 12:36 [PATCH v3 0/8] blk-mq: fix & improve queue quiescing Ming Lei
2017-05-31 12:36 ` [PATCH v3 1/9] blk-mq: introduce blk_mq_unquiesce_queue Ming Lei
2017-05-31 12:36 ` [PATCH v3 2/9] block: introduce flag of QUEUE_FLAG_QUIESCED Ming Lei
2017-05-31 12:37 ` [PATCH v3 3/9] blk-mq: use the introduced blk_mq_unquiesce_queue() Ming Lei
2017-05-31 15:21 ` Bart Van Assche [this message]
2017-06-01 0:54 ` Ming Lei
2017-06-01 23:09 ` Bart Van Assche
2017-06-02 2:00 ` Ming Lei
2017-06-02 22:19 ` Bart Van Assche
2017-05-31 12:37 ` [PATCH v3 4/9] nvme: host: unquiesce queue in nvme_kill_queues() Ming Lei
2017-05-31 12:37 ` [PATCH v3 5/9] blk-mq: fix blk_mq_quiesce_queue Ming Lei
2017-05-31 15:37 ` Bart Van Assche
2017-06-01 2:21 ` Ming Lei
2017-06-01 23:19 ` Bart Van Assche
2017-06-02 2:02 ` Ming Lei
2017-05-31 12:37 ` [PATCH v3 6/9] blk-mq: update comments on blk_mq_quiesce_queue() Ming Lei
2017-05-31 12:37 ` [PATCH v3 7/9] blk-mq: don't stop queue for quiescing Ming Lei
2017-05-31 12:37 ` [PATCH v3 8/9] blk-mq: clarify dispatch may not be drained/blocked by stopping queue Ming Lei
2017-05-31 12:37 ` [PATCH v3 9/9] Revert "blk-mq: don't use sync workqueue flushing from drivers" Ming Lei
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