Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9D75C433EF for ; Mon, 27 Dec 2021 04:04:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235134AbhL0EEf (ORCPT ); Sun, 26 Dec 2021 23:04:35 -0500 Received: from szxga03-in.huawei.com ([45.249.212.189]:30178 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235082AbhL0EEd (ORCPT ); Sun, 26 Dec 2021 23:04:33 -0500 Received: from canpemm500007.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4JMkWf0xGZz8w3F; Mon, 27 Dec 2021 12:02:06 +0800 (CST) Received: from [10.174.179.215] (10.174.179.215) by canpemm500007.china.huawei.com (7.192.104.62) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Mon, 27 Dec 2021 12:04:30 +0800 Subject: Re: [PATCH -next] scsi: storvsc: Fix unsigned comparison to zero To: "Michael Kelley (LINUX)" , KY Srinivasan , Haiyang Zhang , Stephen Hemminger , "wei.liu@kernel.org" , Dexuan Cui , "jejb@linux.ibm.com" , "martin.petersen@oracle.com" , Tianyu Lan , Long Li CC: "linux-hyperv@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20211224120216.35896-1-yuehaibing@huawei.com> From: YueHaibing Message-ID: Date: Mon, 27 Dec 2021 12:04:30 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.215] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500007.china.huawei.com (7.192.104.62) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/12/27 3:49, Michael Kelley (LINUX) wrote: > From: YueHaibing Sent: Friday, December 24, 2021 4:02 AM >> >> The unsigned variable sg_count is being assigned a return value >> from the call to scsi_dma_map() that can return -ENOMEM. >> >> Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver") >> Signed-off-by: YueHaibing > > Good catch! But I wonder if a simpler fix is to just remove the "unsigned" > from the declaration of sg_count. Then we don't need to add the > sg_cnt local variable. A little less complexity is almost always better. :-) Ok， will respine > > Michael > >> --- >> drivers/scsi/storvsc_drv.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c >> index ae293600d799..072c752a8c36 100644 >> --- a/drivers/scsi/storvsc_drv.c >> +++ b/drivers/scsi/storvsc_drv.c >> @@ -1837,7 +1837,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) >> unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length); >> struct scatterlist *sg; >> unsigned long hvpfn, hvpfns_to_add; >> - int j, i = 0; >> + int sg_cnt, j, i = 0; >> >> if (hvpg_count > MAX_PAGE_BUFFER_COUNT) { >> >> @@ -1851,11 +1851,11 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) >> payload->range.len = length; >> payload->range.offset = offset_in_hvpg; >> >> - sg_count = scsi_dma_map(scmnd); >> - if (sg_count < 0) >> + sg_cnt = scsi_dma_map(scmnd); >> + if (sg_cnt < 0) >> return SCSI_MLQUEUE_DEVICE_BUSY; >> >> - for_each_sg(sgl, sg, sg_count, j) { >> + for_each_sg(sgl, sg, sg_cnt, j) { >> /* >> * Init values for the current sgl entry. hvpfns_to_add >> * is in units of Hyper-V size pages. Handling the >> -- >> 2.17.1 > > . >