linux-kernel - Re: [PATCH] MTD: Deletion of checks before the function call "iounmap"

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Message-ID: <20150119175835.GH9759@ld-irv-0074>
Date:	Mon, 19 Jan 2015 09:58:35 -0800
From:	Brian Norris <computersforpeace@...il.com>
To:	SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:	David Woodhouse <dwmw2@...radead.org>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	linux-mtd@...ts.infradead.org, LKML <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org,
	Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH] MTD: Deletion of checks before the function call
 "iounmap"

On Sun, Jan 18, 2015 at 06:08:12PM +0100, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Sun, 18 Jan 2015 17:30:23 +0100
> 
> The iounmap() function performs also input parameter validation.
> Thus the test around the call is not needed.

Is this guaranteed for all arch'es? I expect that it would be, but I see
that, for instance, ARM allows replaceable iounmap() for
subarchitectures. Also, I see checks for various sorts of static
mappings in ARM and x86; these likely (always?) cover the NULL case, but
they're not always straightforward.

Anyway, I'm essentially saying that I'd like to be 100% sure we have a
guarantee before dropping all these.

> This issue was detected by using the Coccinelle software.

What script? Hand-rolled I guess?

Brian
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