From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750894Ab3GXB2B (ORCPT ); Tue, 23 Jul 2013 21:28:01 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:46567 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750729Ab3GXB17 (ORCPT ); Tue, 23 Jul 2013 21:27:59 -0400 Message-ID: <51EF2D9D.8030904@wwwdotorg.org> Date: Tue, 23 Jul 2013 18:27:57 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Joe Perches CC: Wolfram Sang , linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org Subject: Re: [PATCH 10/27] drivers/memory: don't check resource with devm_ioremap_resource References: <1374602524-3398-1-git-send-email-wsa@the-dreams.de> <1374602524-3398-11-git-send-email-wsa@the-dreams.de> <1374603925.3387.26.camel@joe-AO722> In-Reply-To: <1374603925.3387.26.camel@joe-AO722> 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 07/23/2013 11:25 AM, Joe Perches wrote: > On Tue, 2013-07-23 at 20:01 +0200, Wolfram Sang wrote: >> devm_ioremap_resource does sanity checks on the given resource. No need to >> duplicate this in the driver. > > Hi Wolfram: > > This is the first and only one of the patch series I looked at. > >> diff --git a/drivers/memory/tegra20-mc.c b/drivers/memory/tegra20-mc.c > [] >> @@ -218,8 +218,6 @@ static int tegra20_mc_probe(struct platform_device *pdev) >> struct resource *res; >> >> res = platform_get_resource(pdev, IORESOURCE_MEM, i); >> - if (!res) >> - return -ENODEV; >> mc->regs[i] = devm_ioremap_resource(&pdev->dev, res); > > I'm not so sure this is appropriate. > > devm_ioremap_resource returns ERR_PTR(-EINVAL) for > null resource so this changes the return. I think the exact return value is probably pretty arbitrary here. > devm_ioremap_resource also emits a noisy dev_err > message when resource is NULL. > > It's a probe and before the message log would be silent > but now there's a new dmesg. I think those changes are fine, at least for this driver. It's a bug if the required resources are missing, and having probe() actively point out why it's failing can only be a good thing in my book.