From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752010Ab1AXULi (ORCPT ); Mon, 24 Jan 2011 15:11:38 -0500 Received: from mail.bluewatersys.com ([202.124.120.130]:23275 "EHLO hayes.bluewaternz.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750712Ab1AXULh (ORCPT ); Mon, 24 Jan 2011 15:11:37 -0500 Message-ID: <4D3DDD07.1030809@bluewatersys.com> Date: Tue, 25 Jan 2011 09:11:51 +1300 From: Ryan Mallon User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101208 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: Vasiliy Kulikov CC: Julia Lawall , Russell King , kernel-janitors@vger.kernel.org, Nicolas Ferre , Jean-Christophe PLAGNIOL-VILLARD , Andrew Victor , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] arch/arm/mach-at91/clock.c: Add missing IS_ERR test References: <1295898922-18822-1-git-send-email-julia@diku.dk> <1295898922-18822-3-git-send-email-julia@diku.dk> <4D3DD964.9020107@bluewatersys.com> <20110124200515.GA30963@albatros> In-Reply-To: <20110124200515.GA30963@albatros> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/25/2011 09:05 AM, Vasiliy Kulikov wrote: > On Mon, Jan 24, 2011 at 21:00 +0100, Julia Lawall wrote: >> On Tue, 25 Jan 2011, Ryan Mallon wrote: >> >>> On 01/25/2011 08:55 AM, Julia Lawall wrote: >>>> @@ -224,7 +224,7 @@ void __init at91_clock_associate(const char *id, struct device *dev, const char >>>> { >>>> struct clk *clk = clk_get(NULL, id); >>>> >>>> - if (!dev || !clk || !IS_ERR(clk_get(dev, func))) >>>> + if (!dev || IS_ERR(clk) || !IS_ERR(clk_get(dev, func))) >>>> return; >>> >>> I think we want: >>> >>> if (!dev || !clk || IS_ERR(clk) || !IS_ERR(clk_get(dev, func))) >>> return; >>> >>> Since it is valid to return a NULL clk, and we don't want to try and >>> dereference it if that is the case. >> >> Looking at the given defintion of clk_get, I can't see how that could >> happen: > > clk_get() is defined per-architecture, sometimes it is NULL only. Julia is correct. Some architectures can return NULL from clk_get, but I didn't check the at91 before posting :-/. If we can't return NULL from clk_get then we shouldn't bother checking for it. I do think we should drop the !IS_ERR(clk_get(dev, func)) check though. ~Ryan -- Bluewater Systems Ltd - ARM Technology Solution Centre Ryan Mallon 5 Amuri Park, 404 Barbadoes St ryan@bluewatersys.com PO Box 13 889, Christchurch 8013 http://www.bluewatersys.com New Zealand Phone: +64 3 3779127 Freecall: Australia 1800 148 751 Fax: +64 3 3779135 USA 1800 261 2934 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan Mallon Date: Mon, 24 Jan 2011 20:11:51 +0000 Subject: Re: [PATCH 2/4] arch/arm/mach-at91/clock.c: Add missing IS_ERR test Message-Id: <4D3DDD07.1030809@bluewatersys.com> List-Id: References: <1295898922-18822-1-git-send-email-julia@diku.dk> <1295898922-18822-3-git-send-email-julia@diku.dk> <4D3DD964.9020107@bluewatersys.com> <20110124200515.GA30963@albatros> In-Reply-To: <20110124200515.GA30963@albatros> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On 01/25/2011 09:05 AM, Vasiliy Kulikov wrote: > On Mon, Jan 24, 2011 at 21:00 +0100, Julia Lawall wrote: >> On Tue, 25 Jan 2011, Ryan Mallon wrote: >> >>> On 01/25/2011 08:55 AM, Julia Lawall wrote: >>>> @@ -224,7 +224,7 @@ void __init at91_clock_associate(const char *id, struct device *dev, const char >>>> { >>>> struct clk *clk = clk_get(NULL, id); >>>> >>>> - if (!dev || !clk || !IS_ERR(clk_get(dev, func))) >>>> + if (!dev || IS_ERR(clk) || !IS_ERR(clk_get(dev, func))) >>>> return; >>> >>> I think we want: >>> >>> if (!dev || !clk || IS_ERR(clk) || !IS_ERR(clk_get(dev, func))) >>> return; >>> >>> Since it is valid to return a NULL clk, and we don't want to try and >>> dereference it if that is the case. >> >> Looking at the given defintion of clk_get, I can't see how that could >> happen: > > clk_get() is defined per-architecture, sometimes it is NULL only. Julia is correct. Some architectures can return NULL from clk_get, but I didn't check the at91 before posting :-/. If we can't return NULL from clk_get then we shouldn't bother checking for it. I do think we should drop the !IS_ERR(clk_get(dev, func)) check though. ~Ryan -- Bluewater Systems Ltd - ARM Technology Solution Centre Ryan Mallon 5 Amuri Park, 404 Barbadoes St ryan@bluewatersys.com PO Box 13 889, Christchurch 8013 http://www.bluewatersys.com New Zealand Phone: +64 3 3779127 Freecall: Australia 1800 148 751 Fax: +64 3 3779135 USA 1800 261 2934 From mboxrd@z Thu Jan 1 00:00:00 1970 From: ryan@bluewatersys.com (Ryan Mallon) Date: Tue, 25 Jan 2011 09:11:51 +1300 Subject: [PATCH 2/4] arch/arm/mach-at91/clock.c: Add missing IS_ERR test In-Reply-To: <20110124200515.GA30963@albatros> References: <1295898922-18822-1-git-send-email-julia@diku.dk> <1295898922-18822-3-git-send-email-julia@diku.dk> <4D3DD964.9020107@bluewatersys.com> <20110124200515.GA30963@albatros> Message-ID: <4D3DDD07.1030809@bluewatersys.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/25/2011 09:05 AM, Vasiliy Kulikov wrote: > On Mon, Jan 24, 2011 at 21:00 +0100, Julia Lawall wrote: >> On Tue, 25 Jan 2011, Ryan Mallon wrote: >> >>> On 01/25/2011 08:55 AM, Julia Lawall wrote: >>>> @@ -224,7 +224,7 @@ void __init at91_clock_associate(const char *id, struct device *dev, const char >>>> { >>>> struct clk *clk = clk_get(NULL, id); >>>> >>>> - if (!dev || !clk || !IS_ERR(clk_get(dev, func))) >>>> + if (!dev || IS_ERR(clk) || !IS_ERR(clk_get(dev, func))) >>>> return; >>> >>> I think we want: >>> >>> if (!dev || !clk || IS_ERR(clk) || !IS_ERR(clk_get(dev, func))) >>> return; >>> >>> Since it is valid to return a NULL clk, and we don't want to try and >>> dereference it if that is the case. >> >> Looking at the given defintion of clk_get, I can't see how that could >> happen: > > clk_get() is defined per-architecture, sometimes it is NULL only. Julia is correct. Some architectures can return NULL from clk_get, but I didn't check the at91 before posting :-/. If we can't return NULL from clk_get then we shouldn't bother checking for it. I do think we should drop the !IS_ERR(clk_get(dev, func)) check though. ~Ryan -- Bluewater Systems Ltd - ARM Technology Solution Centre Ryan Mallon 5 Amuri Park, 404 Barbadoes St ryan at bluewatersys.com PO Box 13 889, Christchurch 8013 http://www.bluewatersys.com New Zealand Phone: +64 3 3779127 Freecall: Australia 1800 148 751 Fax: +64 3 3779135 USA 1800 261 2934