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

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Date:	Wed, 10 Sep 2014 17:23:44 +0800
From:	Guodong Xu <guodong.xu@...aro.org>
To:	Axel Lin <axel.lin@...ics.com>
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



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().

-Guodong
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