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d="scan'208";a="27401176" Received: from mail-lj1-f197.google.com ([209.85.208.197]) by smtpmx5.ucr.edu with ESMTP/TLS/AES128-GCM-SHA256; 07 Feb 2019 09:48:57 -0800 Received: by mail-lj1-f197.google.com with SMTP id k22-v6so163689ljk.12 for ; Thu, 07 Feb 2019 09:48:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=2h+KsTudxCs800rU2F/cFHz14DOKXOivwjGfmboDlkE=; b=LtnqugqJ5dX2T7LMNDT449Zg3/vqoNvzkJFUK/BY7Sf8CxDTAGpWwwRyria79v2zgA uh5VpcH2nYL59tYUHAC2JRFT5b4EWgBAj1QTgdky7wFffZ/z0KMHVI3Ji+9kYxWkOVXF z5nzKT2hgG//XNmojEl3b73OotSieq+MCIFMrb3TazMwX1NkkFwQenMEp4vlSjHNb8Yl s+DIWgViQEYntX/AZFcSoviisA6vloE+4LsyUyHVMGQ8uhXUHmA7xdTPWAUaRygjh3ys R/MWyrAdwitdZpUUzDQQfPIcDDpI7G2nyFMuug3xdH98fpP4Kr3wiyYcXOX+p1e16NcD ekxA== X-Gm-Message-State: AHQUAuan2k14GlQMFphWatgzE3TesJHQ8g/grBOv6e580CGMfvfmTPe9 cv2YxV/oMlJhJiR0BCSd+lE6WM0bJFXaz7LpLLJjoqKhYMaDDaTsASTnAQSrKLGr32+a3zFBFIJ wGJcKKRM3D31PQe4MyafLaZHzvozHhPVU1A== X-Received: by 2002:a2e:9001:: with SMTP id h1-v6mr6632005ljg.28.1549561735392; Thu, 07 Feb 2019 09:48:55 -0800 (PST) X-Google-Smtp-Source: AHgI3IamVMZFGgUaFIvn9Hr4bdJczD7GZBgzjH9AtRDyXSsBe1CW9j8HHFL/FcBnOQkrEsCWUobngCvfjPanXUy/lrg= X-Received: by 2002:a2e:9001:: with SMTP id h1-v6mr6631981ljg.28.1549561735019; Thu, 07 Feb 2019 09:48:55 -0800 (PST) MIME-Version: 1.0 References: <20190205221559.17545-1-yzhai003@ucr.edu> <20190206.201736.1146228626076916564.davem@davemloft.net> <20190207092454.xq5jvnfnuhcp37nm@flea> In-Reply-To: <20190207092454.xq5jvnfnuhcp37nm@flea> From: Yizhuo Zhai Date: Thu, 7 Feb 2019 09:48:41 -0800 Message-ID: Subject: Re: [PATCH] net: stmmac: Variable "val" in function sun8i_dwmac_set_syscon() could be uninitialized To: Maxime Ripard Cc: David Miller , Chengyu Song , Zhiyun Qian , Giuseppe Cavallaro , Alexandre Torgue , Chen-Yu Tsai , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Make sense, I will send the new patch. Thanks for the opinion. On Thu, Feb 7, 2019 at 1:25 AM Maxime Ripard 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 wrote: > > > > > > Thanks, but why initialization matters here? Is performance the main concern? > > > > > > On Wed, Feb 6, 2019 at 8:17 PM David Miller wrote: > > >> > > >> From: Yizhuo > > >> 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