Re: [PATCH net-next 01/10] drivers: net: xgene: Fix kbuild warning

[Arnd Bergmann]

On Friday, July 29, 2016 5:33:54 PM CEST Iyappan Subramanian wrote:
> This patch fixes the following kbuild warning, when ACPI was not enabled.
> 
> >> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:878:23: warning: 'phy_dev' 
> >> may be used uninitialized in this function [-Wmaybe-uninitialized]
>  phy_dev->advertising = phy_dev->supported;

>From looking at the patch, I don't think it addresses the warning.
Note that Linus added a patch to disable the warning in the latest
mainline kernel, so you won't see it any more, but I think the bug
is still there.

> diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c 
> b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
> index 7714b7d..b6bc6fa 100644
> --- a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
> +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
> @@ -776,15 +776,11 @@ int xgene_enet_phy_connect(struct net_device *ndev)
> netdev_err(ndev, "Could not connect to PHY\n");
> return -ENODEV;
> }
> -
> -   pdata->phy_dev = phy_dev;
> } else {
>  #ifdef CONFIG_ACPI
> struct acpi_device *adev = acpi_phy_find_device(dev);
> if (adev)
> -   pdata->phy_dev =  adev->driver_data;
> -
> -   phy_dev = pdata->phy_dev;
> +   phy_dev =  adev->driver_data;
>  
> if (!phy_dev ||
> phy_connect_direct(ndev, phy_dev, _enet_adjust_link,
> @@ -795,6 +791,7 @@ int xgene_enet_phy_connect(struct net_device *ndev)
>  #endif
> }
>  
> +   pdata->phy_dev = phy_dev;

phy_dev is not initialized anywhere if CONFIG_ACPI is not set
and dev->of_node is NULL (which should not happen in practice,
but the compiler doesn't know that).

I think you want this instead:

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
}
 

ARnd

Arnd

[PATCH net-next 01/10] drivers: net: xgene: Fix kbuild warning

[Iyappan Subramanian]

This patch fixes the following kbuild warning, when ACPI was not enabled.

>> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:878:23: warning: 'phy_dev' 
>> may be used uninitialized in this function [-Wmaybe-uninitialized]
 phy_dev->advertising = phy_dev->supported;

Signed-off-by: Iyappan Subramanian 
---
 drivers/net/ethernet/apm/xgene/xgene_enet_hw.c | 7 ++-
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c 
b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
index 7714b7d..b6bc6fa 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_hw.c
@@ -776,15 +776,11 @@ int xgene_enet_phy_connect(struct net_device *ndev)
netdev_err(ndev, "Could not connect to PHY\n");
return -ENODEV;
}
-
-   pdata->phy_dev = phy_dev;
} else {
 #ifdef CONFIG_ACPI
struct acpi_device *adev = acpi_phy_find_device(dev);
if (adev)
-   pdata->phy_dev =  adev->driver_data;
-
-   phy_dev = pdata->phy_dev;
+   phy_dev =  adev->driver_data;
 
if (!phy_dev ||
phy_connect_direct(ndev, phy_dev, _enet_adjust_link,
@@ -795,6 +791,7 @@ int xgene_enet_phy_connect(struct net_device *ndev)
 #endif
}
 
+   pdata->phy_dev = phy_dev;
pdata->phy_speed = SPEED_UNKNOWN;
phy_dev->supported &= ~SUPPORTED_10baseT_Half &
  ~SUPPORTED_100baseT_Half &
-- 
1.9.1