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

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Message-id: <50849998.2010201@samsung.com>
Date:	Mon, 22 Oct 2012 09:55:52 +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] extcon: driver model release call not needed

On 10/21/2012 01:46 PM, anish kumar wrote:
> From: anish kumar <anish198519851985@...il.com>
> 
> There was a case where free and list_del can be called twice
> on the same pointer.So fixed it by re-arranging the code and
> removing a function which was not needed.
> 
> Signed-off-by: anish kumar <anish198519851985@...il.com>
> ---
>  drivers/extcon/extcon-class.c |   71 ++++++++++++++++++-----------------------
>  1 files changed, 31 insertions(+), 40 deletions(-)
> 
Applied, thanks,

But, There were some minor issue, so I fix and applied it.

[...]

>  static void extcon_dev_release(struct device *dev)
>  {
> -	struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
> -
> -	extcon_cleanup(edev, true);
> +	struct extcon_dev *edev = dev_get_drvdata(dev);
> +	kfree(edev->dev);
It is not necessary to get extcon_dev instance through dev_get_drvdata()
and only call kfree(dev) by using extcon_dev_release()'s parameter.

	kfree(dev);

>  }
>  
>  static const char *muex_name = "mutually_exclusive";
> @@ -810,7 +773,35 @@ EXPORT_SYMBOL_GPL(extcon_dev_register);
>   */
>  void extcon_dev_unregister(struct extcon_dev *edev)
>  {
> -	extcon_cleanup(edev, false);
> +	mutex_lock(&extcon_dev_list_lock);
> +	list_del(&edev->entry);
> +	mutex_unlock(&extcon_dev_list_lock);
> +
> +	if (get_device(edev->dev) != NULL) {

I prefer minimal indentation, so I will modify as below code.

	int index;

	mutex_lock(&extcon_dev_list_lock);
	list_del(&edev->entry);
	mutex_unlock(&extcon_dev_list_lock);

	if (IS_ERR_OR_NULL(get_device(edev->dev))) {
		dev_err(edev->dev, "Failed to unregister extcon_dev (%s)\n",
				dev_name(edev->dev));
		return;
	}

	if (edev->mutually_exclusive && edev->max_supported) {
		for (index = 0; edev->mutually_exclusive[index];
				index++)
			kfree(edev->d_attrs_muex[index].attr.name);
		kfree(edev->d_attrs_muex);
		kfree(edev->attrs_muex);
	}

[...]

Cheers,
Chanwoo Choi
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