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SubjectRe: [PATCH] nfsd: work around a gcc-5.1 warning
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 <arnd@arndb.de>
> ---
> 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 <arnd@arndb.de>
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 <arnd@arndb.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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);

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