linux-kernel - Re: [PATCH 2/3] led-triggers: use atomic kzalloc during led trigger registering

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Message-ID: <CAK5ve-+ZNoiS3qdQ6O543uSAO9L0rr2c=WwuXm-biAqfGfjc7w@mail.gmail.com>
Date:	Tue, 13 Mar 2012 16:50:51 +0800
From:	Bryan Wu <bryan.wu@...onical.com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>,
	Ming Lei <ming.lei@...onical.com>, rpurdie@...ys.net,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux@....linux.org.uk
Subject: Re: [PATCH 2/3] led-triggers: use atomic kzalloc during led trigger registering

On Tue, Mar 13, 2012 at 3:37 AM, Linus Walleij <linus.walleij@...aro.org> wrote:
> 2012/3/10 Bryan Wu <bryan.wu@...onical.com>:
>> 2012/3/8 Uwe Kleine-König <u.kleine-koenig@...gutronix.de>:
>>> On Thu, Mar 08, 2012 at 05:11:02PM +0800, Bryan Wu wrote:
>>>> kzalloc might cause sleep and will generate some warning detected by lockdep,
>>>> when call led_trigger_register_simple on each cpu cores in SMP. This patch fix
>>>> this.
>>> The obvious (and IMHO better) alternative is to call
>>> led_trigger_register_simple from non-atomic context.
>>>
>>> For registering this should be OK, shouldn't it?
>>>
>> Thanks Uwe, it's my bad. I think I should not use on_each_cpu() API to
>> run led_trigger_register_simple. on_each_cpu() will disable interrupt.
>
> It might have been my mistake even so not your fault ... :-)
>

No problem, man. I just simply replaced GFP_KERNEL with GFP_ATOMIC
without thinking deeper.

Best Regards,
-- 
Bryan Wu <bryan.wu@...onical.com>
Kernel Developer    +86.138-1617-6545 Mobile
Canonical Ltd.      www.canonical.com
Ubuntu - Linux for human beings | www.ubuntu.com
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