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@pengutronix.de>
---
 drivers/auxdisplay/img-ascii-lcd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/auxdisplay/img-ascii-lcd.c b/drivers/auxdisplay/img-ascii-lcd.c
index 925c4cd101e9..0c91e39389c1 100644
--- a/drivers/auxdisplay/img-ascii-lcd.c
+++ b/drivers/auxdisplay/img-ascii-lcd.c
@@ -279,13 +279,12 @@ static int img_ascii_lcd_probe(struct platform_device *pdev)
  *
  * Return: 0
  */
-static int img_ascii_lcd_remove(struct platform_device *pdev)
+static void img_ascii_lcd_remove(struct platform_device *pdev)
 {
 	struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev);
 
 	sysfs_remove_link(&pdev->dev.kobj, "message");
 	linedisp_unregister(&ctx->linedisp);
-	return 0;
 }
 
 static struct platform_driver img_ascii_lcd_driver = {
@@ -294,7 +293,7 @@ static struct platform_driver img_ascii_lcd_driver = {
 		.of_match_table	= img_ascii_lcd_matches,
 	},
 	.probe	= img_ascii_lcd_probe,
-	.remove	= img_ascii_lcd_remove,
+	.remove_new = img_ascii_lcd_remove,
 };
 module_platform_driver(img_ascii_lcd_driver);
 
-- 
2.43.0

Hi Uwe,

On Mon, Mar 11, 2024 at 10:59 PM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> 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@pengutronix.de>

Thanks for your patch!

> --- a/drivers/auxdisplay/img-ascii-lcd.c
> +++ b/drivers/auxdisplay/img-ascii-lcd.c
> @@ -279,13 +279,12 @@ static int img_ascii_lcd_probe(struct platform_device *pdev)
>   *
>   * Return: 0

Please remove this line.

>   */
> -static int img_ascii_lcd_remove(struct platform_device *pdev)
> +static void img_ascii_lcd_remove(struct platform_device *pdev)
>  {
>         struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev);
>
>         sysfs_remove_link(&pdev->dev.kobj, "message");
>         linedisp_unregister(&ctx->linedisp);
> -       return 0;
>  }
>
>  static struct platform_driver img_ascii_lcd_driver = {
> @@ -294,7 +293,7 @@ static struct platform_driver img_ascii_lcd_driver = {
>                 .of_match_table = img_ascii_lcd_matches,
>         },
>         .probe  = img_ascii_lcd_probe,
> -       .remove = img_ascii_lcd_remove,
> +       .remove_new = img_ascii_lcd_remove,
>  };
>  module_platform_driver(img_ascii_lcd_driver);

With the above fixed:
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

On Tue, Mar 12, 2024 at 09:17:54AM +0100, Geert Uytterhoeven wrote:
> Hi Uwe,
> 
> On Mon, Mar 11, 2024 at 10:59 PM Uwe Kleine-König
> <u.kleine-koenig@pengutronix.de> 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@pengutronix.de>
> 
> Thanks for your patch!
> 
> > --- a/drivers/auxdisplay/img-ascii-lcd.c
> > +++ b/drivers/auxdisplay/img-ascii-lcd.c
> > @@ -279,13 +279,12 @@ static int img_ascii_lcd_probe(struct platform_device *pdev)
> >   *
> >   * Return: 0
> 
> Please remove this line.

Good catch, thanks.

@Andy: Should I resend this patch? Or the whole series? Or do you want
to fixup while applying?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

On Tue, Mar 12, 2024 at 11:27:37AM +0100, Uwe Kleine-König wrote:
> On Tue, Mar 12, 2024 at 09:17:54AM +0100, Geert Uytterhoeven wrote:
> > On Mon, Mar 11, 2024 at 10:59 PM Uwe Kleine-König
> > <u.kleine-koenig@pengutronix.de> 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@pengutronix.de>
> > 
> > Thanks for your patch!
> > 
> > > --- a/drivers/auxdisplay/img-ascii-lcd.c
> > > +++ b/drivers/auxdisplay/img-ascii-lcd.c
> > > @@ -279,13 +279,12 @@ static int img_ascii_lcd_probe(struct platform_device *pdev)
> > >   *
> > >   * Return: 0
> > 
> > Please remove this line.
> 
> Good catch, thanks.
> 
> @Andy: Should I resend this patch? Or the whole series? Or do you want
> to fixup while applying?

Not big deal, I'll fix it whilst applying.
Thank you!

-- 
With Best Regards,
Andy Shevchenko