From: Chao Leng <lengchao@huawei.com>
To: <linux-nvme@lists.infradead.org>
Cc: kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me
Subject: Re: [PATCH] nvme-core: fix deadlock when delete ctrl due to reconnect fail
Date: Mon, 27 Jul 2020 16:04:57 +0800 [thread overview]
Message-ID: <54e4ef86-53bd-9749-41b5-240c8eb2708c@huawei.com> (raw)
In-Reply-To: <20200727080127.30058-1-lengchao@huawei.com>
Title is error. Ignore this email, see next email.
On 2020/7/27 16:01, Chao Leng wrote:
> A deadlock happens when test link blink for nvme over roce. If time out
> in reconneting process, nvme_rdma_timeout->nvme_rdma_teardown_io_queues
> will quiesce the io queues, and then the ctrl will be deleted after
> reconnect times exceed max_reconnects. If run fdisk from the time
> when the queue is quiesced to the time when the ctrl is deleted,
> delete ctrl will deadlock, the process: nvme_do_delete_ctrl->
> nvme_remove_namespaces->nvme_ns_remove->blk_cleanup_queue->
> blk_freeze_queue->blk_mq_freeze_queue_wait, blk_mq_freeze_queue_wait
> will wait until q_usage_counter of queue become 0, but the queue is
> quiesced, can not clean any request.
>
> Solution: nvme_rdma_timeout should call nvme_start_queues after
> call nvme_rdma_teardown_io_queues. further more, we need start queues
> regardless of whether the remove flag is set, after cancel requests
> in nvme_rdma_teardown_io_queues.
>
> Signed-off-by: Chao Leng <lengchao@huawei.com>
> ---
> drivers/nvme/host/rdma.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
> index f8f856dc0c67..b381e2cde50a 100644
> --- a/drivers/nvme/host/rdma.c
> +++ b/drivers/nvme/host/rdma.c
> @@ -989,8 +989,7 @@ static void nvme_rdma_teardown_io_queues(struct nvme_rdma_ctrl *ctrl,
> nvme_cancel_request, &ctrl->ctrl);
> blk_mq_tagset_wait_completed_request(ctrl->ctrl.tagset);
> }
> - if (remove)
> - nvme_start_queues(&ctrl->ctrl);
> + nvme_start_queues(&ctrl->ctrl);
> nvme_rdma_destroy_io_queues(ctrl, remove);
> }
> }
> @@ -1128,7 +1127,6 @@ static void nvme_rdma_error_recovery_work(struct work_struct *work)
>
> nvme_stop_keep_alive(&ctrl->ctrl);
> nvme_rdma_teardown_io_queues(ctrl, false);
> - nvme_start_queues(&ctrl->ctrl);
> nvme_rdma_teardown_admin_queue(ctrl, false);
> blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);
>
>
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prev parent reply other threads:[~2020-07-27 8:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-27 8:01 [PATCH] nvme-core: fix deadlock when delete ctrl due to reconnect fail Chao Leng
2020-07-27 8:04 ` Chao Leng [this message]
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