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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 76548C28CF6 for ; Thu, 2 Aug 2018 02:01:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1CDB1208A6 for ; Thu, 2 Aug 2018 02:01:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1CDB1208A6 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732007AbeHBDtz (ORCPT ); Wed, 1 Aug 2018 23:49:55 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:10211 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726839AbeHBDtz (ORCPT ); Wed, 1 Aug 2018 23:49:55 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id E74809CA9609A; Thu, 2 Aug 2018 10:01:07 +0800 (CST) Received: from [10.177.253.249] (10.177.253.249) by smtp.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.399.0; Thu, 2 Aug 2018 10:01:07 +0800 Subject: Re: [PATCH v2] net/9p/trans_virtio.c: add null terminal for mount tag To: Dominique Martinet References: <5B6262F4.9080601@huawei.com> <20180802015439.GA27403@nautica> CC: "akpm@linux-foundation.org" , "Eric Van Hensbergen" , Ron Minnich , "Latchesar Ionkov" , Greg Kurz , "Linux Kernel Mailing List" , From: piaojun Message-ID: <5B62658A.3010605@huawei.com> Date: Thu, 2 Aug 2018 09:59:38 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20180802015439.GA27403@nautica> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.253.249] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dominique, On 2018/8/2 9:54, Dominique Martinet wrote: > piaojun wrote on Thu, Aug 02, 2018: >> chan->tag is Non-null terminated which will result in printing messy code >> when debugging code. So we should add '\0' for tag to make the code more >> convenient and robust. In addition, I drop char->tag_len to simplify the >> code. > > Some new lines in commit message would be appreciated. > > That aside, I have a couple of nitpicks, but it looks good to me - thanks > >> >> Signed-off-by: Jun Piao >> --- >> net/9p/trans_virtio.c | 15 +++++---------- >> 1 file changed, 5 insertions(+), 10 deletions(-) >> >> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c >> index d422bfc..0fe9c37 100644 >> --- a/net/9p/trans_virtio.c >> +++ b/net/9p/trans_virtio.c >> @@ -89,10 +89,8 @@ struct virtio_chan { >> unsigned long p9_max_pages; >> /* Scatterlist: can be too big for stack. */ >> struct scatterlist sg[VIRTQUEUE_NUM]; >> - >> - int tag_len; >> /* >> - * tag name to identify a mount Non-null terminated >> + * tag name to identify a mount null terminated >> */ >> char *tag; >> >> @@ -529,10 +527,9 @@ static ssize_t p9_mount_tag_show(struct device *dev, >> vdev = dev_to_virtio(dev); >> chan = vdev->priv; >> >> - memcpy(buf, chan->tag, chan->tag_len); >> - buf[chan->tag_len] = 0; >> + memcpy(buf, chan->tag, strlen(chan->tag) + 1); >> >> - return chan->tag_len + 1; >> + return strlen(chan->tag) + 1; > > Use a local variable for strlen(chan->tag)? > Yes, local variable looks better. >> } >> >> static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); >> @@ -585,7 +582,7 @@ static int p9_virtio_probe(struct virtio_device *vdev) >> err = -EINVAL; >> goto out_free_vq; >> } >> - tag = kmalloc(tag_len, GFP_KERNEL); >> + tag = kzalloc(tag_len + 1, GFP_KERNEL); >> if (!tag) { >> err = -ENOMEM; >> goto out_free_vq; >> @@ -594,7 +591,6 @@ static int p9_virtio_probe(struct virtio_device *vdev) >> virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag), >> tag, tag_len); >> chan->tag = tag; >> - chan->tag_len = tag_len; >> err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); >> if (err) { >> goto out_free_tag; >> @@ -654,8 +650,7 @@ static int p9_virtio_probe(struct virtio_device *vdev) >> >> mutex_lock(&virtio_9p_lock); >> list_for_each_entry(chan, &virtio_chan_list, chan_list) { >> - if (!strncmp(devname, chan->tag, chan->tag_len) && >> - strlen(devname) == chan->tag_len) { >> + if (!strncmp(devname, chan->tag, strlen(chan->tag) + 1)) { > > strncmp(x, y, strlen(y)+1) is precisely what strcmp does so let's use > the simpler version > strcmp looks simpler, and I will wait for a while to hear more suggestions, and then post another patch for these fixes. Thanks, Jun