From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [RFC 04/42] drivers/dma: don't check resource with devm_ioremap_resource Date: Fri, 10 May 2013 13:25:36 -0600 Message-ID: <518D49B0.4050901@wwwdotorg.org> References: <1368173847-5661-1-git-send-email-wsa@the-dreams.de> <1368173847-5661-5-git-send-email-wsa@the-dreams.de> <518D21D4.6000609@wwwdotorg.org> <20130510175739.GA2912@katana> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130510175739.GA2912@katana> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vinod Koul , Dan Williams , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 05/10/2013 11:57 AM, Wolfram Sang wrote: > On Fri, May 10, 2013 at 10:35:32AM -0600, Stephen Warren wrote: >> On 05/10/2013 02:16 AM, Wolfram Sang wrote: >>> devm_ioremap_resource does sanity checks on the given resource. No need to >>> duplicate this in the driver. >> >>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c >> >>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>> - if (!res) { >>> - dev_err(&pdev->dev, "No mem resource for DMA\n"); >>> - return -EINVAL; >>> - } >>> - >>> tdma->base_addr = devm_ioremap_resource(&pdev->dev, res); >> >> One issue here is that it's not obvious just from reading the code >> that's left behind that the "missing" error-checking of the >> platform_get_resource() return value is OK because >> devm_ioremap_resource() will check it "for us". Everyone now has to >> mentally maintain a list of exceptions where it's OK not to error-check. > > My goal is to make not-checking the standard case with devm. OK, if no parameters passed to any devm function every need to be error-checked, that'll certainly be a bit easier to remember. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753863Ab3EJTZl (ORCPT ); Fri, 10 May 2013 15:25:41 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:37483 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753089Ab3EJTZj (ORCPT ); Fri, 10 May 2013 15:25:39 -0400 Message-ID: <518D49B0.4050901@wwwdotorg.org> Date: Fri, 10 May 2013 13:25:36 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Wolfram Sang CC: linux-kernel@vger.kernel.org, Vinod Koul , Dan Williams , linux-tegra@vger.kernel.org Subject: Re: [RFC 04/42] drivers/dma: don't check resource with devm_ioremap_resource References: <1368173847-5661-1-git-send-email-wsa@the-dreams.de> <1368173847-5661-5-git-send-email-wsa@the-dreams.de> <518D21D4.6000609@wwwdotorg.org> <20130510175739.GA2912@katana> In-Reply-To: <20130510175739.GA2912@katana> X-Enigmail-Version: 1.4.6 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 05/10/2013 11:57 AM, Wolfram Sang wrote: > On Fri, May 10, 2013 at 10:35:32AM -0600, Stephen Warren wrote: >> On 05/10/2013 02:16 AM, Wolfram Sang wrote: >>> devm_ioremap_resource does sanity checks on the given resource. No need to >>> duplicate this in the driver. >> >>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c >> >>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>> - if (!res) { >>> - dev_err(&pdev->dev, "No mem resource for DMA\n"); >>> - return -EINVAL; >>> - } >>> - >>> tdma->base_addr = devm_ioremap_resource(&pdev->dev, res); >> >> One issue here is that it's not obvious just from reading the code >> that's left behind that the "missing" error-checking of the >> platform_get_resource() return value is OK because >> devm_ioremap_resource() will check it "for us". Everyone now has to >> mentally maintain a list of exceptions where it's OK not to error-check. > > My goal is to make not-checking the standard case with devm. OK, if no parameters passed to any devm function every need to be error-checked, that'll certainly be a bit easier to remember.