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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B95DBC28CF6 for ; Thu, 2 Aug 2018 01:54:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48677208A3 for ; Thu, 2 Aug 2018 01:54:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48677208A3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codewreck.org 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 S1732292AbeHBDni (ORCPT ); Wed, 1 Aug 2018 23:43:38 -0400 Received: from nautica.notk.org ([91.121.71.147]:55480 "EHLO nautica.notk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731503AbeHBDni (ORCPT ); Wed, 1 Aug 2018 23:43:38 -0400 Received: by nautica.notk.org (Postfix, from userid 1001) id 22291C009; Thu, 2 Aug 2018 03:54:54 +0200 (CEST) Date: Thu, 2 Aug 2018 03:54:39 +0200 From: Dominique Martinet To: piaojun Cc: "akpm@linux-foundation.org" , Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , Greg Kurz , Linux Kernel Mailing List , v9fs-developer@lists.sourceforge.net Subject: Re: [PATCH v2] net/9p/trans_virtio.c: add null terminal for mount tag Message-ID: <20180802015439.GA27403@nautica> References: <5B6262F4.9080601@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5B6262F4.9080601@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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)? > } > > 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 -- Dominique