linux-kernel - Re: [PATCH] [PATCH] extcon: driver model release call not needed

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Message-id: <50820E5F.2010000@samsung.com>
Date:	Sat, 20 Oct 2012 11:37:19 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	anish kumar <anish198519851985@...il.com>
Cc:	gregkh@...uxfoundation.org, myungjoo.ham@...sung.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [PATCH] extcon: driver model release call not needed

On 10/20/2012 11:30 AM, anish kumar wrote:
> On Sat, 2012-10-20 at 10:57 +0900, Chanwoo Choi wrote:
>> On 10/19/2012 02:12 AM, anish kumar wrote:
>>> From: anish kumar <anish198519851985@...il.com>
>>>
>>> We don't need a release call in this file as we are doing
>>> everything needed in unregister call and we don't have any
>>> more pointer to free up.
>>>
>>> Signed-off-by: anish kumar <anish198519851985@...il.com>
>>> ---
>>>  drivers/extcon/extcon-class.c |    4 +---
>>>  1 files changed, 1 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c
>>> index 946a318..cf30eb1 100644
>>> --- a/drivers/extcon/extcon-class.c
>>> +++ b/drivers/extcon/extcon-class.c
>>> @@ -585,9 +585,7 @@ static void extcon_cleanup(struct extcon_dev *edev, bool skip)
>>>  
>>>  static void extcon_dev_release(struct device *dev)
>>>  {
>>> -	struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
>>> -
>>> -	extcon_cleanup(edev, true);
>>> +	/* We don't have any thing to free here */
>>>  }
>>>  
>>>  static const char *muex_name = "mutually_exclusive";
>>
>> I can't agree this patch. The extcon_dev_release() function is used
>> for dev->release. If some case without calling extcon_dev_unregister(),
>> I think dev->release function is needed to free memory of edev->dev.
> Is it not being released by extcon_dev_unregister?
> I think it is released by that and we will do two times free and
> list_del(&edev->entry) as it is called by extcon_dev_release also.

I think that this patch should modify it as below patch to remove
two call of kfree().  How about you?

diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c
index e717bbc..efca0b4 100644
--- a/drivers/extcon/extcon-class.c
+++ b/drivers/extcon/extcon-class.c
@@ -597,9 +597,8 @@ static void extcon_cleanup(struct extcon_dev *edev, bool skip)
 #endif
                device_unregister(edev->dev);
                put_device(edev->dev);
-       }
-
-       kfree(edev->dev);
+       } else {
+               kfree(edev->dev);

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