[PATCH 00/10] usb: musb: Convert to platform remove callback returning void

[PATCH 00/10] usb: musb: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this patch series adapts the platform drivers below drivers/usb/musb
to use the .remove_new() callback. Compared to the traditional .remove()
callback .remove_new() returns no value. This is a good thing because
the driver core doesn't (and cannot) cope for errors during remove. The
only effect of a non-zero return value in .remove() is that the driver
core emits a warning. The device is removed anyhow and an early return
from .remove() usually yields a resource leak.

By changing the remove callback to return void driver authors cannot
reasonably assume any more that there is some kind of cleanup later.

All drivers touched here returned zero unconditionally in their remove
callback, so they could all be converted trivially to .remove_new().

Best regards
Uwe

Uwe Kleine-König (10):
  usb: musb: da8xx: Convert to platform remove callback returning void
  usb: musb: jz4740: Convert to platform remove callback returning void
  usb: musb: mediatek: Convert to platform remove callback returning void
  usb: musb: mpfs: Convert to platform remove callback returning void
  usb: musb: musb_core: Convert to platform remove callback returning void
  usb: musb: musb_dsps: Convert to platform remove callback returning void
  usb: musb: omap2430: Convert to platform remove callback returning void
  usb: musb: sunxi: Convert to platform remove callback returning void
  usb: musb: tusb6010: Convert to platform remove callback returning void
  usb: musb: ux500: Convert to platform remove callback returning void

 drivers/usb/musb/da8xx.c     | 6 ++----
 drivers/usb/musb/jz4740.c    | 6 ++----
 drivers/usb/musb/mediatek.c  | 6 ++----
 drivers/usb/musb/mpfs.c      | 6 ++----
 drivers/usb/musb/musb_core.c | 5 ++---
 drivers/usb/musb/musb_dsps.c | 6 ++----
 drivers/usb/musb/omap2430.c  | 6 ++----
 drivers/usb/musb/sunxi.c     | 6 ++----
 drivers/usb/musb/tusb6010.c  | 6 ++----
 drivers/usb/musb/ux500.c     | 6 ++----
 10 files changed, 20 insertions(+), 39 deletions(-)

base-commit: fe15c26ee26efa11741a7b632e9f23b01aca4cc6
-- 
2.39.2

[PATCH 02/10] usb: musb: jz4740: Convert to platform remove callback returning void

[Uwe Kleine-König]

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 (mostly) ignored
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.

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/usb/musb/jz4740.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/musb/jz4740.c b/drivers/usb/musb/jz4740.c
index c7b1d2a394d9..5aabdd7e2511 100644
--- a/drivers/usb/musb/jz4740.c
+++ b/drivers/usb/musb/jz4740.c
@@ -308,14 +308,12 @@ static int jz4740_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int jz4740_remove(struct platform_device *pdev)
+static void jz4740_remove(struct platform_device *pdev)
 {
 	struct jz4740_glue *glue = platform_get_drvdata(pdev);
 
 	platform_device_unregister(glue->pdev);
 	clk_disable_unprepare(glue->clk);
-
-	return 0;
 }
 
 static const struct of_device_id jz4740_musb_of_match[] = {
@@ -327,7 +325,7 @@ MODULE_DEVICE_TABLE(of, jz4740_musb_of_match);
 
 static struct platform_driver jz4740_driver = {
 	.probe		= jz4740_probe,
-	.remove		= jz4740_remove,
+	.remove_new	= jz4740_remove,
 	.driver		= {
 		.name	= "musb-jz4740",
 		.of_match_table = jz4740_musb_of_match,
-- 
2.39.2

Re: [PATCH 02/10] usb: musb: jz4740: Convert to platform remove callback returning void

[Paul Cercueil]

Le mercredi 05 avril 2023 à 16:10 +0200, Uwe Kleine-König a écrit :
> 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 (mostly)
> ignored
> 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.
> 
> 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>

Reviewed-by: Paul Cercueil <paul@crapouillou.net>

Cheers,
-Paul

> ---
>  drivers/usb/musb/jz4740.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/musb/jz4740.c b/drivers/usb/musb/jz4740.c
> index c7b1d2a394d9..5aabdd7e2511 100644
> --- a/drivers/usb/musb/jz4740.c
> +++ b/drivers/usb/musb/jz4740.c
> @@ -308,14 +308,12 @@ static int jz4740_probe(struct platform_device
> *pdev)
>         return ret;
>  }
>  
> -static int jz4740_remove(struct platform_device *pdev)
> +static void jz4740_remove(struct platform_device *pdev)
>  {
>         struct jz4740_glue *glue = platform_get_drvdata(pdev);
>  
>         platform_device_unregister(glue->pdev);
>         clk_disable_unprepare(glue->clk);
> -
> -       return 0;
>  }
>  
>  static const struct of_device_id jz4740_musb_of_match[] = {
> @@ -327,7 +325,7 @@ MODULE_DEVICE_TABLE(of, jz4740_musb_of_match);
>  
>  static struct platform_driver jz4740_driver = {
>         .probe          = jz4740_probe,
> -       .remove         = jz4740_remove,
> +       .remove_new     = jz4740_remove,
>         .driver         = {
>                 .name   = "musb-jz4740",
>                 .of_match_table = jz4740_musb_of_match,

Re: [PATCH 02/10] usb: musb: jz4740: Convert to platform remove callback returning void

[Philippe Mathieu-Daudé]

On 5/4/23 16:10, 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 (mostly) ignored
> 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.
> 
> 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/usb/musb/jz4740.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>