Re: [PATCH] net: ethernet: mtk_eth_soc: fix error checking in mtk_mac_config()

[Tom Rix]

On 1/9/22 4:43 PM, Jakub Kicinski wrote:
> On Sat,  8 Jan 2022 07:50:03 -0800 trix@xxxxxxxxxx wrote:
> > From: Tom Rix <trix@xxxxxxxxxx>
> >
> > Clang static analysis reports this problem
> > mtk_eth_soc.c:394:7: warning: Branch condition evaluates
> >    to a garbage value
> >                  if (err)
> >                      ^~~
> >
> > err is not initialized and only conditionally set.
> > Check err consistently with the rest of mtk_mac_config(),
> > after even possible setting.
> >
> > Fixes: 7e538372694b ("net: ethernet: mediatek: Re-add support SGMII")
> > Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> > ---
> >   drivers/net/ethernet/mediatek/mtk_eth_soc.c | 12 +++++++-----
> >   1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> > index b67b4323cff08..a27e548488584 100644
> > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> > @@ -385,14 +385,16 @@ static void mtk_mac_config(struct phylink_config *config, unsigned int mode,
> >   		       0 : mac->id;
> >   
> >   		/* Setup SGMIISYS with the determined property */
> > -		if (state->interface != PHY_INTERFACE_MODE_SGMII)
> > +		if (state->interface != PHY_INTERFACE_MODE_SGMII) {
> >   			err = mtk_sgmii_setup_mode_force(eth->sgmii, sid,
> >   							 state);
> > -		else if (phylink_autoneg_inband(mode))
> > +			if (err)
> > +				goto init_err;
> > +		} else if (phylink_autoneg_inband(mode)) {
> >   			err = mtk_sgmii_setup_mode_an(eth->sgmii, sid);
> > -
> > -		if (err)
> > -			goto init_err;
> > +			if (err)
> > +				goto init_err;
> > +		}
> >   
> >   		regmap_update_bits(eth->ethsys, ETHSYS_SYSCFG0,
> >   				   SYSCFG0_SGMII_MASK, val);
> Why not init err to 0 before the if or add an else err = 0; branch?

This is the way I would have preferred to do it but the function's 
existing error handling does it this way.

I'll respin the patch.

Tom


>