From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752177AbcAZTIp (ORCPT ); Tue, 26 Jan 2016 14:08:45 -0500 Received: from mx4-phx2.redhat.com ([209.132.183.25]:58112 "EHLO mx4-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751103AbcAZTIm (ORCPT ); Tue, 26 Jan 2016 14:08:42 -0500 Date: Tue, 26 Jan 2016 14:08:13 -0500 (EST) From: Bob Peterson To: Arnd Bergmann Cc: Steven Whitehouse , linux-arm-kernel@lists.infradead.org, cluster-devel@redhat.com, linux-kernel@vger.kernel.org Message-ID: <1232643434.15889153.1453835293754.JavaMail.zimbra@redhat.com> In-Reply-To: <1453735996-1958733-2-git-send-email-arnd@arndb.de> References: <1453735996-1958733-1-git-send-email-arnd@arndb.de> <1453735996-1958733-2-git-send-email-arnd@arndb.de> Subject: Re: [PATCH] gfs2: avoid uninitialized variable warning MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.3.113.122] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF43 (Linux)/8.0.6_GA_5922) Thread-Topic: gfs2: avoid uninitialized variable warning Thread-Index: p1EBBiXixlYjIAC1gIYB5p9dMOvGOg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- > We get a bogus warning about a potential uninitialized variable > use in gfs2, because the compiler does not figure out that we > never use the leaf number if get_leaf_nr() returns an error: > > fs/gfs2/dir.c: In function 'get_first_leaf': > fs/gfs2/dir.c:802:9: warning: 'leaf_no' may be used uninitialized in this > function [-Wmaybe-uninitialized] > fs/gfs2/dir.c: In function 'dir_split_leaf': > fs/gfs2/dir.c:1021:8: warning: 'leaf_no' may be used uninitialized in this > function [-Wmaybe-uninitialized] > > Changing the 'if (!error)' to 'if (!IS_ERR_VALUE(error))' is > sufficient to let gcc understand that this is exactly the same > condition as in IS_ERR() so it can optimize the code path enough > to understand it. > > Signed-off-by: Arnd Bergmann > --- > fs/gfs2/dir.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c > index 6a92592304fb..d4014af4f064 100644 > --- a/fs/gfs2/dir.c > +++ b/fs/gfs2/dir.c > @@ -798,7 +798,7 @@ static int get_first_leaf(struct gfs2_inode *dip, u32 > index, > int error; > > error = get_leaf_nr(dip, index, &leaf_no); > - if (!error) > + if (!IS_ERR_VALUE(error)) > error = get_leaf(dip, leaf_no, bh_out); > > return error; > @@ -1014,7 +1014,7 @@ static int dir_split_leaf(struct inode *inode, const > struct qstr *name) > > index = name->hash >> (32 - dip->i_depth); > error = get_leaf_nr(dip, index, &leaf_no); > - if (error) > + if (IS_ERR_VALUE(error)) > return error; > > /* Get the old leaf block */ > -- > 2.7.0 > > Hi, Thanks. This is now applied to the for-next branch of the linux-gfs2 tree: https://git.kernel.org/cgit/linux/kernel/git/gfs2/linux-gfs2.git/commit/fs/gfs2?h=for-next&id=07cfdc3071432a07713e4d007c2811e0224490b0 Regards, Bob Peterson Red Hat File Systems