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=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 402FCC433DB for ; Thu, 28 Jan 2021 09:19:15 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9E12964DD6 for ; Thu, 28 Jan 2021 09:19:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E12964DD6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=HVZ+ou9x/aQpmpEHJ5nn7LYrRZCAXPJ1C5yxXRUjIPQ=; b=um+Ko4Hj+64F7Iihz0RkJBWHT quAvjiFxKFR3rksEe0xHUGnuEEChtHsIsNd64PFobwatnnC2Grg911M31jt5aBvpz/HpBsEyB4VZK HvBQbDJo9b2C+JEv9NHXBMPVE1j6b/JmaTwFvR5KLkEEgMe6kir8sN8et5X23qjANyhd+aYcl7xTf F283noUQe5F3bt3vfZfZvoEH5TeFE2CFctSGQQLZWvr3/ykMBQtBdRpu+EALzeT+pk9f1/YVuZ6Pm DuW7HkE13WUHu1FfR5Un/jCMHb0Ddc4itUNe35cYyI7zTQ1mZsPV+LzazF3G77eDz0yI9yeZPN2Rc dg/qPX2qQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l53SF-0000HO-Hr; Thu, 28 Jan 2021 09:19:07 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l53SC-0000GS-7g for linux-nvme@lists.infradead.org; Thu, 28 Jan 2021 09:19:05 +0000 Received: from DGGEMM405-HUB.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4DRFGf5zyKzW2PM; Thu, 28 Jan 2021 17:16:58 +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 17:18:58 +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 17:18:57 +0800 Subject: Re: [PATCH v2] nvme-multipath: Early exit if no path is available To: Daniel Wagner References: <20210127103033.15318-1-dwagner@suse.de> <20210128075837.u5u56t23fq5gu6ou@beryllium.lan> From: Chao Leng Message-ID: <69575290-200e-b4a1-4269-c71e4c2cc37b@huawei.com> Date: Thu, 28 Jan 2021 17:18:56 +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: <20210128075837.u5u56t23fq5gu6ou@beryllium.lan> Content-Language: en-US X-Originating-IP: [10.169.42.93] X-ClientProxiedBy: dggeme708-chm.china.huawei.com (10.1.199.104) To dggema772-chm.china.huawei.com (10.1.198.214) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210128_041904_560182_13817F4C X-CRM114-Status: GOOD ( 12.53 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sagi Grimberg , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Jens Axboe , Hannes Reinecke , Keith Busch , Christoph Hellwig Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 2021/1/28 15:58, Daniel Wagner wrote: > On Thu, Jan 28, 2021 at 09:31:30AM +0800, Chao Leng wrote: >>> --- 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". > > The problem is when we enter nvme_round_robin_path() and there is no > path available. In this case the initialization ns = nvme_next_ns(head, > old) could return a NULL pointer."old" should not be NULL, so there is at least one path that is "old". It is impossible to return NULL for nvme_next_ns(head, old). > . > _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme