linux-kernel - Re: [PATCH 4/5] regulator: of: add missing of_node

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Date:	Mon, 12 Oct 2015 21:58:28 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Julia Lawall <julia.lawall@...6.fr>
Cc:	k.kozlowski.k@...il.com, Liam Girdwood <lgirdwood@...il.com>,
	kernel-janitors@...r.kernel.org, Mark Brown <broonie@...nel.org>,
	linux-kernel@...r.kernel.org,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Andrew Lunn <andrew@...n.ch>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Jason Cooper <jason@...edaemon.net>
Subject: Re: [PATCH 4/5] regulator: of: add missing of_node_put

W dniu 12.10.2015 o 21:44, Julia Lawall pisze:
> 
> 
> On Mon, 12 Oct 2015, Krzysztof Kozlowski wrote:
> 
>> 2015-10-10 21:30 GMT+09:00 Julia Lawall <Julia.Lawall@...6.fr>:
>>>
>>> for_each_child_of_node performs an of_node_get on each iteration, so
>>> a break out of the loop requires an of_node_put.
>>>
>>> The semantic patch that fixes this problem is as follows
>>> (http://coccinelle.lip6.fr):
>>>
>>> // <smpl>
>>> @@
>>> expression root,e;
>>> local idexpression child;
>>> @@
>>>
>>>  for_each_child_of_node(root, child) {
>>>    ... when != of_node_put(child)
>>>        when != e = child
>>> (
>>>    return child;
>>> |
>>> +  of_node_put(child);
>>> ?  return ...;
>>> )
>>>    ...
>>>  }
>>> // </smpl>
>>>
>>> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
>>>
>>> ---
>>>  drivers/regulator/of_regulator.c |    1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
>>> index 499e437..f9d77b4 100644
>>> --- a/drivers/regulator/of_regulator.c
>>> +++ b/drivers/regulator/of_regulator.c
>>> @@ -274,6 +274,7 @@ int of_regulator_match(struct device *dev, struct device_node *node,
>>>                                 dev_err(dev,
>>>                                         "failed to parse DT for regulator %s\n",
>>>                                         child->name);
>>> +                               of_node_put(child);
>>
>> This looks good.
>>
>>>                                 return -EINVAL;
>>>                         }
>>>                         match->of_node = of_node_get(child);
>>
>> But what about 'break' few lines below? The reference from last
>> of_get_next_child() should be also dropped because... or we should
>> remove this of_node_get() call.
> 
> Actually, the break is OK.  It's on the inner for loop, not the
> for_each_child_of_node loop.  The for_each_child_of_node will still
> decrement the reference count in the normal way.
> 
> julia

Yes, you're right. The patch looks good:
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>

Best regards,
Krzysztof

>> How about fixing also usage of for_each_available_child_of_node() in
>> regulator_of_get_init_data()?
>>
>> Best regards,
>> Krzysztof
>> --
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