Re: [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning

From: Or Gerlitz
Date: Sat Oct 01 2016 - 11:08:22 EST

On Fri, Sep 30, 2016 at 7:17 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> Build-testing this driver with -Wmaybe-uninitialized gives a new false-positive
> warning that I can't really explain:
> drivers/net/ethernet/mellanox/mlx5/core/en_tc.c: In function 'mlx5e_configure_flower':
> drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:509:3: error: 'old_attr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> It's obvious from the code that 'old_attr' is initialized whenever 'old'
> is non-NULL here. The warning appears with all versions I tested from gcc-4.7
> through gcc-6.1, and I could not come up with a way to rewrite the function
> in a more readable way that avoids the warning, so I'm adding another
> initialization to shut it up.
> Fixes: 8b32580df1cb ("net/mlx5e: Add TC vlan action for SRIOV offloads")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Yeah, this is clearly false positive and I was sure that newish GCCs
don't show that, but you are the master here.. so FWIW

Acked-by: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>