Return-Path: Received: from fieldses.org ([173.255.197.46]:45045 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752555AbbEMSLo (ORCPT ); Wed, 13 May 2015 14:11:44 -0400 Date: Wed, 13 May 2015 14:11:43 -0400 From: "J. Bruce Fields" To: Arnd Bergmann Cc: linux-nfs@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] nfsd: work around a gcc-5.1 warning Message-ID: <20150513181143.GD2827@fieldses.org> References: <2121336.tAfQfAWQ2u@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <2121336.tAfQfAWQ2u@wuerfel> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, May 12, 2015 at 11:31:29PM +0200, Arnd Bergmann wrote: > gcc-5.0 warns about a potential uninitialized variable use in nfsd: > > fs/nfsd/nfs4state.c: In function 'nfsd4_process_open2': > fs/nfsd/nfs4state.c:3781:3: warning: 'old_deny_bmap' may be used uninitialized in this function [-Wmaybe-uninitialized] > reset_union_bmap_deny(old_deny_bmap, stp); > ^ > fs/nfsd/nfs4state.c:3760:16: note: 'old_deny_bmap' was declared here > unsigned char old_deny_bmap; > ^ > > This is a false positive, the code path that is warned about cannot > actually be reached. > > This adds an initialization for the variable to make the warning go > away. > > Signed-off-by: Arnd Bergmann > --- > This warning shows up in some ARM defconfig builds, which we try to > build with no warnings to detect regressions. OK, I guess. How about simplifying slightly and doing it this way?--b commit 3ae81ac291ec Author: Arnd Bergmann Date: Tue May 12 23:31:29 2015 +0200 nfsd: work around a gcc-5.1 warning gcc-5.0 warns about a potential uninitialized variable use in nfsd: fs/nfsd/nfs4state.c: In function 'nfsd4_process_open2': fs/nfsd/nfs4state.c:3781:3: warning: 'old_deny_bmap' may be used uninitialized in this function [-Wmaybe-uninitialized] reset_union_bmap_deny(old_deny_bmap, stp); ^ fs/nfsd/nfs4state.c:3760:16: note: 'old_deny_bmap' was declared here unsigned char old_deny_bmap; ^ This is a false positive, the code path that is warned about cannot actually be reached. This adds an initialization for the variable to make the warning go away. Signed-off-by: Arnd Bergmann Signed-off-by: J. Bruce Fields diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 86f5c273c9ec..aef7c9bb6114 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3861,7 +3861,7 @@ static __be32 nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp, struct nfsd4_open *open) { __be32 status; - unsigned char old_deny_bmap; + unsigned char old_deny_bmap = stp->st_deny_bmap; if (!test_access(open->op_share_access, stp)) return nfs4_get_vfs_file(rqstp, fp, cur_fh, stp, open); @@ -3870,7 +3870,6 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *c spin_lock(&fp->fi_lock); status = nfs4_file_check_deny(fp, open->op_share_deny); if (status == nfs_ok) { - old_deny_bmap = stp->st_deny_bmap; set_deny(open->op_share_deny, stp); fp->fi_share_deny |= (open->op_share_deny & NFS4_SHARE_DENY_BOTH);