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Date:   Thu, 7 Feb 2019 10:24:54 +0100
From:   Maxime Ripard <maxime.ripard@bootlin.com>
To:     Yizhuo Zhai <yzhai003@ucr.edu>
Cc:     David Miller <davem@davemloft.net>,
        Chengyu Song <csong@cs.ucr.edu>,
        Zhiyun Qian <zhiyunq@cs.ucr.edu>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Chen-Yu Tsai <wens@csie.org>, netdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: stmmac: Variable "val" in function
 sun8i_dwmac_set_syscon() could be uninitialized
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On Wed, Feb 06, 2019 at 09:53:16PM -0800, Yizhuo Zhai wrote:
>=20
>=20
> On Wed, Feb 6, 2019 at 9:52 PM Yizhuo Zhai <yzhai003@ucr.edu> wrote:
> >
> > Thanks, but why initialization matters here? Is performance the main co=
ncern?
> >
> > On Wed, Feb 6, 2019 at 8:17 PM David Miller <davem@davemloft.net> wrote:
> >>
> >> From: Yizhuo <yzhai003@ucr.edu>
> >> Date: Tue,  5 Feb 2019 14:15:59 -0800
> >>
> >> > @@ -639,9 +639,14 @@ static int sun8i_dwmac_set_syscon(struct stmmac=
_priv *priv)
> >> >       struct sunxi_priv_data *gmac =3D priv->plat->bsp_priv;
> >> >       struct device_node *node =3D priv->device->of_node;
> >> >       int ret;
> >> > -     u32 reg, val;
> >> > +     u32 reg, val =3D 0;
> >> > +
> >> > +     ret =3D regmap_read(gmac->regmap, SYSCON_EMAC_REG, &val);
> >> > +     if (ret) {
> >> > +             dev_err(priv->device, "Fail to read SYSCON_EMAC_REG.\n=
");
> >> > +             return ret;
> >> > +     }
> >>
> >> I agree with the other reviewer that since you check 'ret' the initial=
ization of
> >> 'val' is no longer needed.
>
> Thanks, but why initialization matters here? Is performance the main
> concern?

Not really, but if we turn this the other way around, why should we do
something that doesn't bring anything?

Maxime

--=20
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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