linux-kernel - Re: [PATCH] regulator: remove unnecessary of_node

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Message-ID: <CAFRkauCCv71fPnCAiqzaSVtn=3cWUr1vzgyyOAEnUoX7S_4RGg@mail.gmail.com>
Date:	Wed, 10 Sep 2014 17:51:00 +0800
From:	Axel Lin <axel.lin@...ics.com>
To:	Guodong Xu <guodong.xu@...aro.org>
Cc:	Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	Support Opensource <support.opensource@...semi.com>
Subject: Re: [PATCH] regulator: remove unnecessary of_node_get() to parent

2014-09-10 17:23 GMT+08:00 Guodong Xu <guodong.xu@...aro.org>:
>
>
> On 09/10/2014 12:23 PM, Axel Lin wrote:
>> 2014-09-10 12:20 GMT+08:00 Axel Lin <axel.lin@...ics.com>:
>>> 2014-09-10 11:50 GMT+08:00 Guodong Xu <guodong.xu@...aro.org>:
>>>> These of_node_get() were added to balance refcount decrements inside of
>>>> of_find_node_by_name().
>>>> See: commit c92f5dd2c42f ("regulator: Add missing of_node_put()")
>>>>
>>>> However of_find_node_by_name() was then replaced by of_get_child_by_name(),
>>>> which doesn't call of_node_put() against its input parameter.
>>>>
>>>> So, need to remove these unnecessary of_node_get() calls.
>>>
>>> The of_node_get() and of_node_put() is a pair.
>>> You need to either keep both or remove both.
>>>
>>>
>>> BTW,
>>> I think either the comment of of_get_child_by_name() needs fix or the
>>> implementation
>>> needs fix. The implementation does not increment refcount.
>>
>> Ah, I see the of_node_get() and of_node_put() in __of_get_next_child.
>> So of_get_child_by_name() is correct.(both comment and implementation)
>>
>
> That's right. You only need to call of_node_put() once on the node
> of_get_child_by_name() returns. That's why I submit this patch to remove
> of_node_get() _before_ calling to of_get_child_by_name().

Reviewed-by: Axel Lin <axel.lin@...ics.com>

Thanks,
Axel
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