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=-15.2 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 1A863C433DB for ; Thu, 28 Jan 2021 01:33:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE44964DDA for ; Thu, 28 Jan 2021 01:33:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231520AbhA1Bdu (ORCPT ); Wed, 27 Jan 2021 20:33:50 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:2969 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231410AbhA1BcZ (ORCPT ); Wed, 27 Jan 2021 20:32:25 -0500 Received: from DGGEMM405-HUB.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4DR2wB6nWYz5L7Y; Thu, 28 Jan 2021 09:30:18 +0800 (CST) Received: from dggema772-chm.china.huawei.com (10.1.198.214) by DGGEMM405-HUB.china.huawei.com (10.3.20.213) with Microsoft SMTP Server (TLS) id 14.3.498.0; Thu, 28 Jan 2021 09:31:32 +0800 Received: from [10.169.42.93] (10.169.42.93) by dggema772-chm.china.huawei.com (10.1.198.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2106.2; Thu, 28 Jan 2021 09:31:31 +0800 Subject: Re: [PATCH v2] nvme-multipath: Early exit if no path is available To: Daniel Wagner , CC: Sagi Grimberg , , "Jens Axboe" , Hannes Reinecke , Keith Busch , Christoph Hellwig References: <20210127103033.15318-1-dwagner@suse.de> From: Chao Leng Message-ID: Date: Thu, 28 Jan 2021 09:31:30 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20210127103033.15318-1-dwagner@suse.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.169.42.93] X-ClientProxiedBy: dggeme704-chm.china.huawei.com (10.1.199.100) To dggema772-chm.china.huawei.com (10.1.198.214) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/1/27 18:30, Daniel Wagner wrote: > nvme_round_robin_path() should test if the return ns pointer is > valid. nvme_next_ns() will return a NULL pointer if there is no path > left. > > Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy") > Cc: Hannes Reinecke > Signed-off-by: Daniel Wagner > --- > v2: > - moved NULL test into the if conditional statement > - added Fixes tag > > drivers/nvme/host/multipath.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c > index 9ac762b28811..282b7a4ea9a9 100644 > --- a/drivers/nvme/host/multipath.c > +++ b/drivers/nvme/host/multipath.c > @@ -221,7 +221,7 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head, > } > > for (ns = nvme_next_ns(head, old); > - ns != old; > + ns && ns != old; nvme_round_robin_path just be called when !"old". nvme_next_ns should not return NULL when !"old". It seems unnecessary to add checking "ns". Is there a bug that "old" in not in "head" list? If yes, we should fix it. > ns = nvme_next_ns(head, ns)) { > if (nvme_path_is_disabled(ns)) > continue; >