From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [RFC 04/42] drivers/dma: don't check resource with devm_ioremap_resource Date: Sun, 12 May 2013 20:28:07 +0200 Message-ID: <20130512182802.GA2922@katana> 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> <518D49B0.4050901@wwwdotorg.org> <20130512160440.GA27639@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20130512160440.GA27639-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Vinod Koul Cc: Stephen Warren , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Dan Williams , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On Sun, May 12, 2013 at 09:34:40PM +0530, Vinod Koul wrote: > On Fri, May 10, 2013 at 01:25:36PM -0600, Stephen Warren wrote: > > 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. > Okay to remove the log message and move to devm_ but I dont agree with this > patch not returning error above. We shouldnt supress the error.. The error will be reported because devm_ioremap_resource will return an ERR_PTR. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751203Ab3ELS0v (ORCPT ); Sun, 12 May 2013 14:26:51 -0400 Received: from sauhun.de ([89.238.76.85]:59608 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751011Ab3ELS0t (ORCPT ); Sun, 12 May 2013 14:26:49 -0400 Date: Sun, 12 May 2013 20:28:07 +0200 From: Wolfram Sang To: Vinod Koul Cc: Stephen Warren , linux-kernel@vger.kernel.org, Dan Williams , linux-tegra@vger.kernel.org Subject: Re: [RFC 04/42] drivers/dma: don't check resource with devm_ioremap_resource Message-ID: <20130512182802.GA2922@katana> 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> <518D49B0.4050901@wwwdotorg.org> <20130512160440.GA27639@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130512160440.GA27639@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 12, 2013 at 09:34:40PM +0530, Vinod Koul wrote: > On Fri, May 10, 2013 at 01:25:36PM -0600, Stephen Warren wrote: > > 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. > Okay to remove the log message and move to devm_ but I dont agree with this > patch not returning error above. We shouldnt supress the error.. The error will be reported because devm_ioremap_resource will return an ERR_PTR.