Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757627AbcCCLo5 (ORCPT ); Thu, 3 Mar 2016 06:44:57 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:33312 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757239AbcCCLox (ORCPT ); Thu, 3 Mar 2016 06:44:53 -0500 Subject: Re: [PATCH v2] watchdog: tangox_wdt: test clock rate to avoid division by 0 To: Wolfram Sang , linux-kernel@vger.kernel.org References: <1456993453-7958-1-git-send-email-wsa@the-dreams.de> Cc: Wim Van Sebroeck , linux-watchdog@vger.kernel.org From: Guenter Roeck Message-ID: <56D823B2.6040004@roeck-us.net> Date: Thu, 3 Mar 2016 03:44:50 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1456993453-7958-1-git-send-email-wsa@the-dreams.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1576 Lines: 55 On 03/03/2016 12:24 AM, Wolfram Sang wrote: > From: Wolfram Sang > > The clk API may return 0 on clk_get_rate, so we should check the result before > using it as a divisor. For this, refactor the code to use a central > error path. > > Signed-off-by: Wolfram Sang Reviewed-by: Guenter Roeck > --- > drivers/watchdog/tangox_wdt.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/drivers/watchdog/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c > index 709c1ed6fd79b9..cfbed7e051b619 100644 > --- a/drivers/watchdog/tangox_wdt.c > +++ b/drivers/watchdog/tangox_wdt.c > @@ -139,6 +139,10 @@ static int tangox_wdt_probe(struct platform_device *pdev) > return err; > > dev->clk_rate = clk_get_rate(dev->clk); > + if (!dev->clk_rate) { > + err = -EINVAL; > + goto err; > + } > > dev->wdt.parent = &pdev->dev; > dev->wdt.info = &tangox_wdt_info; > @@ -171,10 +175,8 @@ static int tangox_wdt_probe(struct platform_device *pdev) > } > > err = watchdog_register_device(&dev->wdt); > - if (err) { > - clk_disable_unprepare(dev->clk); > - return err; > - } > + if (err) > + goto err; > > platform_set_drvdata(pdev, dev); > > @@ -187,6 +189,10 @@ static int tangox_wdt_probe(struct platform_device *pdev) > dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n"); > > return 0; > + > + err: > + clk_disable_unprepare(dev->clk); > + return err; > } > > static int tangox_wdt_remove(struct platform_device *pdev) >