From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 10/27] drivers/memory: don't check resource with devm_ioremap_resource Date: Tue, 23 Jul 2013 18:27:57 -0700 Message-ID: <51EF2D9D.8030904@wwwdotorg.org> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1374603925.3387.26.camel@joe-AO722> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Joe Perches Cc: Wolfram Sang , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@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.