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From: Chao Leng <lengchao@huawei.com>
To: Sagi Grimberg <sagi@grimberg.me>, <linux-nvme@lists.infradead.org>
Cc: kbusch@kernel.org, axboe@fb.com, hch@lst.de
Subject: Re: [PATCH 0/3] avoid race between time out and tear down
Date: Thu, 22 Oct 2020 09:58:25 +0800	[thread overview]
Message-ID: <1903f0fa-7dd3-6e87-0e4e-502628822e89@huawei.com> (raw)
In-Reply-To: <db872ac4-662c-1e47-291a-7c64ae0cfa57@grimberg.me>



On 2020/10/21 16:53, Sagi Grimberg wrote:
> 
>>>>>> Avoid race between time out and tear down for rdma and tcp.
>>>>>
>>>>> This patchset overall looks good, but we still need the patch that
>>>>> avoids double completion:
>>>>>
>>>>> -- 
>>>>> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
>>>>> index 629b025685d1..46428ff0b0fc 100644
>>>>> --- a/drivers/nvme/host/tcp.c
>>>>> +++ b/drivers/nvme/host/tcp.c
>>>>> @@ -2175,7 +2175,7 @@ static void nvme_tcp_complete_timed_out(struct request *rq)
>>>>>          /* fence other contexts that may complete the command */
>>>>>          mutex_lock(&to_tcp_ctrl(ctrl)->teardown_lock);
>>>>>          nvme_tcp_stop_queue(ctrl, nvme_tcp_queue_id(req->queue));
>>>>> -       if (!blk_mq_request_completed(rq)) {
>>>>> +       if (blk_mq_request_started(rq) && !blk_mq_request_completed(rq)) {
>>>> Yes, this patch is need. and samely for nvme_cancel_request.
>>>> This will fix the race with asynchronous completion.
>>>>
>>>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>>>> index e85f6304efd7..1e838d952096 100644
>>>> --- a/drivers/nvme/host/core.c
>>>> +++ b/drivers/nvme/host/core.c
>>>> @@ -338,7 +338,7 @@ bool nvme_cancel_request(struct request *req, void *data, bool reserved)
>>>>                                  "Cancelling I/O %d", req->tag);
>>>>
>>>>          /* don't abort one completed request */
>>>> -       if (blk_mq_request_completed(req))
>>>> +       if (blk_mq_request_completed(req) || !blk_mq_request_started(rq))
>>>>                  return true;
>>>>
>>>>          nvme_req(req)->status = NVME_SC_HOST_ABORTED_CMD;
>>>
>>> This one is unneeded because blk_mq_tagset_busy_iter checks that the
>>> request has started...
>> Yes, it is already checked.
> 
> Can you add the attached patches and resend?
> 
> You can also add my:
> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
ok, I will do it later.

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      reply	other threads:[~2020-10-22  1:58 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20  9:08 [PATCH 0/3] avoid race between time out and tear down Chao Leng
2020-10-20 18:43 ` Sagi Grimberg
2020-10-21  2:16   ` Chao Leng
2020-10-21  4:59     ` Sagi Grimberg
2020-10-21  6:51       ` Chao Leng
2020-10-21  8:53         ` Sagi Grimberg
2020-10-22  1:58           ` Chao Leng [this message]

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