linux-kernel - Re: [PATCH 10/27] drivers/memory: don't check resource with devm_ioremap

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Date:	Tue, 23 Jul 2013 11:25:25 -0700
From:	Joe Perches <joe@...ches.com>
To:	Wolfram Sang <wsa@...-dreams.de>
Cc:	linux-kernel@...r.kernel.org,
	Stephen Warren <swarren@...dotorg.org>,
	linux-tegra@...r.kernel.org
Subject: Re: [PATCH 10/27] drivers/memory: don't check resource with
 devm_ioremap_resource

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.

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.

Perhaps that should be mentioned in the changelog here
and elsewhere in the series.


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