Re: [PATCH] net: stmmac: Variable "val" in function sun8i_dwmac_set_syscon() could be uninitialized

From: Yizhuo Zhai <yzhai003@ucr.edu>
To: Maxime Ripard <maxime.ripard@bootlin.com>
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
Date: Thu, 7 Feb 2019 09:48:41 -0800	[thread overview]
Message-ID: <CABvMjLS2ftUgxeKNxQW2npxKRjM3_=U7qg7oYTw6VrkUWcOocw@mail.gmail.com> (raw)
In-Reply-To: <20190207092454.xq5jvnfnuhcp37nm@flea>

Make sense, I will send the new patch. Thanks for the opinion.

On Thu, Feb 7, 2019 at 1:25 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> On Wed, Feb 06, 2019 at 09:53:16PM -0800, Yizhuo Zhai wrote:
> >
> >
> > 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 concern?
> > >
> > > 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 = priv->plat->bsp_priv;
> > >> >       struct device_node *node = priv->device->of_node;
> > >> >       int ret;
> > >> > -     u32 reg, val;
> > >> > +     u32 reg, val = 0;
> > >> > +
> > >> > +     ret = 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 initialization 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
>
> --
> Maxime Ripard, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

-- 
Kind Regards,

Yizhuo Zhai

Computer Science, Graduate Student
University of California, Riverside