[PATCH] net: xgene: fix maybe-uninitialized variable

[PATCH] net: xgene: fix maybe-uninitialized variable

[Arnd Bergmann]

Building with -Wmaybe-uninitialized shows a potential use of
an uninitialized variable:

drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: In function 'xgene_enet_phy_connect':
drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:802:23: warning: 'phy_dev' may be used uninitialized in this function [-Wmaybe-uninitialized]

Although the compiler correctly identified this based on the function,
the current code is still safe as long dev->of_node is non-NULL
for the case of CONFIG_ACPI=n, which is currently the case.

The warning is now disabled by default, but still appears when
building with W=1, and other build test tools should be able to
detect it as well. Adding an #else clause here makes the code
more robust and makes it clear to the compiler that this cannot
happen.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 8089a96f601b ("drivers: net: xgene: Add backward compatibility")
---
 drivers/net/ethernet/apm/xgene/xgene_enet_hw.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
index 7714b7d4026a..98779fe2d558 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
@@ -792,6 +792,8 @@ int xgene_enet_phy_connect(struct net_device *ndev)
 			netdev_err(ndev, "Could not connect to PHY\n");
 			return  -ENODEV;
 		}
+#else
+		return -ENODEV;
 #endif
 	}
 
-- 
2.9.0

Re: [PATCH] net: xgene: fix maybe-uninitialized variable

[David Miller]

From: Arnd Bergmann <arnd@arndb.de>
Date: Tue,  2 Aug 2016 12:23:29 +0200

> Building with -Wmaybe-uninitialized shows a potential use of
> an uninitialized variable:
> 
> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: In function 'xgene_enet_phy_connect':
> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:802:23: warning: 'phy_dev' may be used uninitialized in this function [-Wmaybe-uninitialized]
> 
> Although the compiler correctly identified this based on the function,
> the current code is still safe as long dev->of_node is non-NULL
> for the case of CONFIG_ACPI=n, which is currently the case.
> 
> The warning is now disabled by default, but still appears when
> building with W=1, and other build test tools should be able to
> detect it as well. Adding an #else clause here makes the code
> more robust and makes it clear to the compiler that this cannot
> happen.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: 8089a96f601b ("drivers: net: xgene: Add backward compatibility")

Applied.