Re: [PATCH] USB: apple-mfi-fastcharge: Use devm_kzalloc and simplify the code

[Greg Kroah-Hartman]

On Sat, Nov 14, 2020 at 12:42:49PM +0000, Lucas Tanure wrote:
> Signed-off-by: Lucas Tanure <tanure@xxxxxxxxx>

I can't take patches without any changelog text, sorry.

> ---
>  drivers/usb/misc/apple-mfi-fastcharge.c | 17 +++++------------
>  1 file changed, 5 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/usb/misc/apple-mfi-fastcharge.c b/drivers/usb/misc/apple-mfi-fastcharge.c
> index 9de0171b5177..de86e389a008 100644
> --- a/drivers/usb/misc/apple-mfi-fastcharge.c
> +++ b/drivers/usb/misc/apple-mfi-fastcharge.c
> @@ -178,16 +178,13 @@ static int mfi_fc_probe(struct usb_device *udev)
>  {
>  	struct power_supply_config battery_cfg = {};
>  	struct mfi_device *mfi = NULL;
> -	int err;
>  
>  	if (!mfi_fc_match(udev))
>  		return -ENODEV;
>  
> -	mfi = kzalloc(sizeof(struct mfi_device), GFP_KERNEL);
> -	if (!mfi) {
> -		err = -ENOMEM;
> -		goto error;
> -	}
> +	mfi = devm_kzalloc(&udev->dev, sizeof(*mfi), GFP_KERNEL);
> +	if (!mfi)
> +		return -ENOMEM;
>  
>  	battery_cfg.drv_data = mfi;
>  
> @@ -197,8 +194,7 @@ static int mfi_fc_probe(struct usb_device *udev)
>  						&battery_cfg);
>  	if (IS_ERR(mfi->battery)) {
>  		dev_err(&udev->dev, "Can't register battery\n");
> -		err = PTR_ERR(mfi->battery);
> -		goto error;
> +		return PTR_ERR(mfi->battery);
>  	}
>  
>  	mfi->udev = usb_get_dev(udev);
> @@ -206,9 +202,6 @@ static int mfi_fc_probe(struct usb_device *udev)
>  
>  	return 0;
>  
> -error:
> -	kfree(mfi);
> -	return err;
>  }
>  
>  static void mfi_fc_disconnect(struct usb_device *udev)
> @@ -220,7 +213,7 @@ static void mfi_fc_disconnect(struct usb_device *udev)
>  		power_supply_unregister(mfi->battery);
>  	dev_set_drvdata(&udev->dev, NULL);
>  	usb_put_dev(mfi->udev);
> -	kfree(mfi);
> +	devm_kfree(&udev->dev, mfi);

Are you sure about this?

And what's wrong with the existing code?  Using the devm_*() variants
seems like a "cleanup", but it's not always the case.

thanks,

greg k-h