[PATCH AUTOSEL 3.18 08/10] s390: ctcm: fix ctcm_new_device error return code

From: Sasha Levin
Date: Tue May 07 2019 - 01:44:21 EST

From: Arnd Bergmann <arnd@xxxxxxxx>

[ Upstream commit 27b141fc234a3670d21bd742c35d7205d03cbb3a ]

clang points out that the return code from this function is
undefined for one of the error paths:

../drivers/s390/net/ctcm_main.c:1595:7: warning: variable 'result' is used uninitialized whenever 'if' condition is true
if (priv->channel[direction] == NULL) {
../drivers/s390/net/ctcm_main.c:1638:9: note: uninitialized use occurs here
return result;
../drivers/s390/net/ctcm_main.c:1595:3: note: remove the 'if' if its condition is always false
if (priv->channel[direction] == NULL) {
../drivers/s390/net/ctcm_main.c:1539:12: note: initialize the variable 'result' to silence this warning
int result;

Make it return -ENODEV here, as in the related failure cases.
gcc has a known bug in underreporting some of these warnings
when it has already eliminated the assignment of the return code
based on some earlier optimization step.

Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/s390/net/ctcm_main.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index e056dd4fe44d..5526388f905e 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -1595,6 +1595,7 @@ static int ctcm_new_device(struct ccwgroup_device *cgdev)
if (priv->channel[direction] == NULL) {
if (direction == CTCM_WRITE)
+ result = -ENODEV;
goto out_dev;
priv->channel[direction]->netdev = dev;