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: Wed, 21 Oct 2020 14:51:46 +0800 [thread overview]
Message-ID: <5a48d20f-e9c9-5d37-776a-1fe3b1eb79a8@huawei.com> (raw)
In-Reply-To: <b60f34ea-86f1-ef86-8e1f-b156b7681699@grimberg.me>
On 2020/10/21 12:59, 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.
> .
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next prev parent reply other threads:[~2020-10-21 6:52 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 [this message]
2020-10-21 8:53 ` Sagi Grimberg
2020-10-22 1:58 ` Chao Leng
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