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[3.16-stable,09/87] gfs2: avoid uninitialized variable warning

Message ID 20170505194745.3627137-10-arnd@arndb.de
State Accepted
Commit 67893f12e5374bbcaaffbc6e570acbc2714ea884
Headers show
Series build warnings and errors | expand

Commit Message

Arnd Bergmann May 5, 2017, 7:46 p.m. UTC 
commit 67893f12e5374bbcaaffbc6e570acbc2714ea884 upstream.

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 <arnd@arndb.de>

Signed-off-by: Bob Peterson <rpeterso@redhat.com>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 fs/gfs2/dir.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.9.0
diff mbox series

Patch

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 5d4261ff5d23..9291cf5e7439 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -764,7 +764,7 @@  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;
@@ -980,7 +980,7 @@  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  */