linux-kernel - Re: [RFC PATCH 3/7] hwmon: raspberry-pi: Clean-up few drivers by using managed work init

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Date:   Sat, 13 Feb 2021 13:16:52 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     mazziesaccount@...il.com, Guenter Roeck <linux@...ck-us.net>,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org
Subject: Re: [RFC PATCH 3/7] hwmon: raspberry-pi: Clean-up few drivers by
 using managed work init

On Sat, Feb 13, 2021 at 02:07:02PM +0200, Matti Vaittinen wrote:
> Few drivers implement remove call-back only for ensuring a delayed
> work gets cancelled prior driver removal. Clean-up these by switching
> to use devm_delayed_work_autocancel() instead.
> 
> This change is compile-tested only. All testing is appreciated.
> 
> Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
> ---
>  drivers/hwmon/raspberrypi-hwmon.c | 16 +++++-----------
>  1 file changed, 5 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c
> index d3a64a35f7a9..acfa674932bc 100644
> --- a/drivers/hwmon/raspberrypi-hwmon.c
> +++ b/drivers/hwmon/raspberrypi-hwmon.c
> @@ -106,6 +106,7 @@ static int rpi_hwmon_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct rpi_hwmon_data *data;
> +	int ret;
>  
>  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
> @@ -119,7 +120,10 @@ static int rpi_hwmon_probe(struct platform_device *pdev)
>  							       &rpi_chip_info,
>  							       NULL);
>  
> -	INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll);
> +	ret = devm_delayed_work_autocancel(dev, &data->get_values_poll_work,
> +					   get_values_poll);
> +	if (ret)
> +		return ret;
>  	platform_set_drvdata(pdev, data);
>  
>  	if (!PTR_ERR_OR_ZERO(data->hwmon_dev))
> @@ -128,18 +132,8 @@ static int rpi_hwmon_probe(struct platform_device *pdev)
>  	return PTR_ERR_OR_ZERO(data->hwmon_dev);
>  }
>  
> -static int rpi_hwmon_remove(struct platform_device *pdev)
> -{
> -	struct rpi_hwmon_data *data = platform_get_drvdata(pdev);
> -
> -	cancel_delayed_work_sync(&data->get_values_poll_work);
> -
> -	return 0;
> -}
> -
>  static struct platform_driver rpi_hwmon_driver = {
>  	.probe = rpi_hwmon_probe,
> -	.remove = rpi_hwmon_remove,
>  	.driver = {
>  		.name = "raspberrypi-hwmon",
>  	},

So if I manually unbind the driver from the device, and then unload the
driver, what happens?

thanks,

greg k-h