From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECD4FC433DB for ; Thu, 21 Jan 2021 09:00:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD9F5239D1 for ; Thu, 21 Jan 2021 09:00:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728124AbhAUI74 (ORCPT ); Thu, 21 Jan 2021 03:59:56 -0500 Received: from mx2.suse.de ([195.135.220.15]:39960 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727420AbhAUI7h (ORCPT ); Thu, 21 Jan 2021 03:59:37 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id CE63CAD0B; Thu, 21 Jan 2021 08:58:40 +0000 (UTC) Subject: Re: [PATCH v3 3/5] nvme-fabrics: avoid double request completion for nvmf_fail_nonready_command To: Chao Leng , linux-nvme@lists.infradead.org Cc: axboe@kernel.dk, linux-block@vger.kernel.org, sagi@grimberg.me, axboe@fb.com, kbusch@kernel.org, hch@lst.de References: <20210121070330.19701-1-lengchao@huawei.com> <20210121070330.19701-4-lengchao@huawei.com> From: Hannes Reinecke Message-ID: Date: Thu, 21 Jan 2021 09:58:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20210121070330.19701-4-lengchao@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 1/21/21 8:03 AM, Chao Leng wrote: > When reconnect, the request may be completed with NVME_SC_HOST_PATH_ERROR > in nvmf_fail_nonready_command. The state of request will be changed to > MQ_RQ_IN_FLIGHT before call nvme_complete_rq. If free the request > asynchronously such as in nvme_submit_user_cmd, in extreme scenario > the request may be completed again in tear down process. > nvmf_fail_nonready_command do not need calling blk_mq_start_request > before complete the request. nvmf_fail_nonready_command should set > the state of request to MQ_RQ_COMPLETE before complete the request. > So what you are saying is that there is a race condition between blk_mq_start_request() and nvme_complete_request() > Signed-off-by: Chao Leng > --- > drivers/nvme/host/fabrics.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c > index 72ac00173500..874e4320e214 100644 > --- a/drivers/nvme/host/fabrics.c > +++ b/drivers/nvme/host/fabrics.c > @@ -553,9 +553,7 @@ blk_status_t nvmf_fail_nonready_command(struct nvme_ctrl *ctrl, > !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH)) > return BLK_STS_RESOURCE; > > - nvme_req(rq)->status = NVME_SC_HOST_PATH_ERROR; > - blk_mq_start_request(rq); > - nvme_complete_rq(rq); > + nvme_complete_failed_req(rq); > return BLK_STS_OK; > } > EXPORT_SYMBOL_GPL(nvmf_fail_nonready_command); > I'd rather have 'nvme_complete_failed_req()' accept the status as argument, like nvme_complete_failed_request(rq, NVME_SC_HOST_PATH_ERROR) that way it's obvious what is happening, and the status isn't hidden in the function. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer