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

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Date:	Wed, 10 Sep 2014 12:20:00 +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 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.

/**
 *      of_get_child_by_name - Find the child node by name for a given parent
 *      @node:  parent node
 *      @name:  child name to look for.
 *
 *      This function looks for child node for given matching name
 *
 *      Returns a node pointer if found, with refcount incremented, use
 *      of_node_put() on it when done.
 *      Returns NULL if node is not found.
 */

struct device_node *of_get_child_by_name(const struct device_node *node,
                                const char *name)
{
        struct device_node *child;

        for_each_child_of_node(node, child)
                if (child->name && (of_node_cmp(child->name, name) == 0))
                        break;
        return child;
}
EXPORT_SYMBOL(of_get_child_by_name);
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