linux-kernel - Re: [PATCH RESEND 6/6] clk: s5p-g2d: Fix incorrect usage of IS_ERR_OR

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Date:	Thu, 03 Jan 2013 00:14:38 +0100
From:	Sylwester Nawrocki <sylvester.nawrocki@...il.com>
To:	Dan Carpenter <error27@...il.com>,
	Tony Prisk <linux@...sktech.co.nz>
CC:	Sergei Shtylyov <sshtylyov@...sta.com>,
	kernel-janitors@...r.kernel.org,
	Tomasz Stanislawski <t.stanislaws@...sung.com>,
	linux-kernel@...r.kernel.org,
	Kyungmin Park <kyungmin.park@...sung.com>,
	linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: Re: [PATCH RESEND 6/6] clk: s5p-g2d: Fix incorrect usage of IS_ERR_OR_NULL

On 01/02/2013 06:10 AM, Dan Carpenter wrote:
> clk_get() returns NULL if CONFIG_HAVE_CLK is disabled.

It's not a problem for this driver, as it never dereferences what's
returned from clk_get(). It would have to include <plat/clock.h>, which
it doesn't and which would have clearly indicated abuse of the clock API.

Moreover, this driver now depends on architectures that select HAVE_CLK,
so it couldn't be build when CONFIG_HAVE_CLK is disabled.

> I told Tony about this but everyone has been gone with end of year
> holidays so it hasn't been addressed.
>
> Tony, please fix it so people don't apply these patches until
> clk_get() is updated to not return NULL.  It sucks to have to revert
> patches.

As explained by Russell many times, the clock API users should not care
whether the value returned from clk_get() is NULL or not. It should only
be tested with IS_ERR(). The patches look fine to me, no need to do
anything.

---

Regards,
Sylwester
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