Re: [PATCH] net: xgene: fix backward compatibility fix

From: David Miller
Date: Thu Sep 01 2016 - 17:47:27 EST


From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Mon, 29 Aug 2016 14:37:14 +0200

> A bugfix for backward compatibility handling introduced undefined
> behavior for the case that of_parse_phandle() does not return
> a valid entry, as "gcc -Wmaybe-unused" reports:
>
> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: In function 'xgene_enet_phy_connect':
> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:776:6: error: 'phy_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: In function 'xgene_enet_mdio_config':
> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c:776:6: error: 'phy_dev' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> We can work around this by removing the check for zero "np", as
> of_phy_connect() will correctly handle a NULL argument so we fall
> back into the normal error handling case.
>
> Note that I had previously fixed another bug that resulted in the
> exact same warning, but this is a different problem that was
> introduced after my original fix.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Fixes: 03377e381bf4 ("drivers: net: xgene: Fix backward compatibility")

Applied.