linux-kernel - Re: [PATCH] auxdisplay: seg-led-gpio: Convert to platform remove callback returning void

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Message-ID: <ba9558d8-13d2-416f-834e-e03835abea07@alliedtelesis.co.nz>
Date: Tue, 9 Apr 2024 20:28:27 +0000
From: Chris Packham <Chris.Packham@...iedtelesis.co.nz>
To: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	Andy Shevchenko <andy@...nel.org>
CC: Geert Uytterhoeven <geert@...ux-m68k.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "kernel@...gutronix.de"
	<kernel@...gutronix.de>
Subject: Re: [PATCH] auxdisplay: seg-led-gpio: Convert to platform remove
 callback returning void


On 9/04/24 21:03, Uwe Kleine-König wrote:
> The .remove() callback for a platform driver returns an int which makes
> many driver authors wrongly assume it's possible to do error handling by
> returning an error code. However the value returned is ignored (apart
> from emitting a warning) and this typically results in resource leaks.
>
> To improve here there is a quest to make the remove callback return
> void. In the first step of this quest all drivers are converted to
> .remove_new(), which already returns void. Eventually after all drivers
> are converted, .remove_new() will be renamed to .remove().
>
> Trivially convert this driver from always returning zero in the remove
> callback to the void returning variant.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>

Reviewed-by: Chris Packham <chris.packham@...iedtelesis.co.nz>


> ---
>   drivers/auxdisplay/seg-led-gpio.c | 6 ++----
>
> Hello,
>
> the drivers below of drivers/auxdisplay were already converted to struct
> platform_driver::remove_new during the v6.9-rc1 development cycle. This
> driver was added for v6.9-rc1 still using the old prototype.
>
> There are still more drivers to be converted, so there is from my side
> no need to get this into v6.9, but the next merge window would be nice.
>
> Best regards
> Uwe
>   1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/auxdisplay/seg-led-gpio.c b/drivers/auxdisplay/seg-led-gpio.c
> index 35a8dbb1e9d2..183ab3011cbb 100644
> --- a/drivers/auxdisplay/seg-led-gpio.c
> +++ b/drivers/auxdisplay/seg-led-gpio.c
> @@ -81,14 +81,12 @@ static int seg_led_probe(struct platform_device *pdev)
>   	return linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops);
>   }
>   
> -static int seg_led_remove(struct platform_device *pdev)
> +static void seg_led_remove(struct platform_device *pdev)
>   {
>   	struct seg_led_priv *priv = platform_get_drvdata(pdev);
>   
>   	cancel_delayed_work_sync(&priv->work);
>   	linedisp_unregister(&priv->linedisp);
> -
> -	return 0;
>   }
>   
>   static const struct of_device_id seg_led_of_match[] = {
> @@ -99,7 +97,7 @@ MODULE_DEVICE_TABLE(of, seg_led_of_match);
>   
>   static struct platform_driver seg_led_driver = {
>   	.probe = seg_led_probe,
> -	.remove = seg_led_remove,
> +	.remove_new = seg_led_remove,
>   	.driver = {
>   		.name = "seg-led-gpio",
>   		.of_match_table = seg_led_of_match,
>
> base-commit: 4cece764965020c22cff7665b18a012006359095