nfsd: work around a gcc-5.1 warning

PATCH In review Arnd Bergmann 2 participants 3 messages May 12, 2015 – May 13, 2015

Subsystems (2)

NFS client NFS server

lore

Share & tools

lore

Arnd Bergmann

author

2015-05-12 21:31 UTC #0 lore raw

PATCH 1/1 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 <[email protected]>

---
This warning shows up in some ARM defconfig builds, which we try to build with no warnings to detect regressions.

fs/nfsd/nfs4state.c +2 -0

index 38f2d7abe3a7..997eda362a75 100644
@@ -3770,6 +3770,8 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *c
 		set_deny(open->op_share_deny, stp);
 		fp->fi_share_deny |=
 				(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
+	} else {
+		old_deny_bmap = 0;
 	}
 	spin_unlock(&fp->fi_lock);

J. Bruce Fields

2015-05-13 18:11 UTC #1 lore raw

Quoted 13 lines · Arnd Bergmann

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.

Quoted 7 lines

This adds an initialization for the variable to make the warning go away.
Signed-off-by Arnd Bergmann <[email protected]>
---
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 <[email protected]>
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:

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 <[email protected]>

Signed-off-by J. Bruce Fields <[email protected]>

fs/nfsd/nfs4state.c +1 -2

index 86f5c273c9ec..aef7c9bb6114 100644
@@ -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);

Arnd Bergmann

author

2015-05-13 18:59 UTC #2 lore raw

Quoted 19 lines · On Wednesday 13 May 2015 14:11:43 J. Bruce Fields wrote:

OK, I guess. How about simplifying slightly and doing it this way?--b
commit 3ae81ac291ec
Author: Arnd Bergmann <[email protected]>
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;
^

Quoted 10 lines

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 <[email protected]>
Signed-off-by J. Bruce Fields <[email protected]>

Works for me, thanks!

Arnd