[PATCH 0/2] parport: Convert to platform remove callback returning void

[PATCH 0/2] parport: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this series converts all drivers below drivers/parport to use
.remove_new(). See commit 5c5a7680e67b ("platform: Provide a remove
callback that returns no value") for an extended explanation and the
eventual goal. The TL;DR; is to make it harder for driver authors to
leak resources without noticing.

This is merge window material. The two patches are independent of each
other, so they could be applied individually.

Best regards
Uwe

Uwe Kleine-König (2):
  parport: amiga: Convert to platform remove callback returning void
  parport: sunbpp: Convert to platform remove callback returning void

 drivers/parport/parport_amiga.c  | 5 ++---
 drivers/parport/parport_sunbpp.c | 6 ++----
 2 files changed, 4 insertions(+), 7 deletions(-)


base-commit: ceb2fe0d438644e1de06b9a6468a1fb8e2199c70
-- 
2.42.0

[PATCH 1/2] parport: amiga: 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 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/parport/parport_amiga.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/parport/parport_amiga.c b/drivers/parport/parport_amiga.c
index 84d5701d606c..e6dc857aac3f 100644
--- a/drivers/parport/parport_amiga.c
+++ b/drivers/parport/parport_amiga.c
@@ -219,7 +219,7 @@ static int __init amiga_parallel_probe(struct platform_device *pdev)
 	return err;
 }
 
-static int __exit amiga_parallel_remove(struct platform_device *pdev)
+static void __exit amiga_parallel_remove(struct platform_device *pdev)
 {
 	struct parport *port = platform_get_drvdata(pdev);
 
@@ -227,11 +227,10 @@ static int __exit amiga_parallel_remove(struct platform_device *pdev)
 	if (port->irq != PARPORT_IRQ_NONE)
 		free_irq(IRQ_AMIGA_CIAA_FLG, port);
 	parport_put_port(port);
-	return 0;
 }
 
 static struct platform_driver amiga_parallel_driver = {
-	.remove = __exit_p(amiga_parallel_remove),
+	.remove_new = __exit_p(amiga_parallel_remove),
 	.driver   = {
 		.name	= "amiga-parallel",
 	},
-- 
2.42.0

[PATCH 2/2] parport: sunbpp: 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 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/parport/parport_sunbpp.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/parport/parport_sunbpp.c b/drivers/parport/parport_sunbpp.c
index c81d4d86994b..949236a7a27c 100644
--- a/drivers/parport/parport_sunbpp.c
+++ b/drivers/parport/parport_sunbpp.c
@@ -334,7 +334,7 @@ static int bpp_probe(struct platform_device *op)
 	return err;
 }
 
-static int bpp_remove(struct platform_device *op)
+static void bpp_remove(struct platform_device *op)
 {
 	struct parport *p = dev_get_drvdata(&op->dev);
 	struct parport_operations *ops = p->ops;
@@ -351,8 +351,6 @@ static int bpp_remove(struct platform_device *op)
 	kfree(ops);
 
 	dev_set_drvdata(&op->dev, NULL);
-
-	return 0;
 }
 
 static const struct of_device_id bpp_match[] = {
@@ -370,7 +368,7 @@ static struct platform_driver bpp_sbus_driver = {
 		.of_match_table = bpp_match,
 	},
 	.probe		= bpp_probe,
-	.remove		= bpp_remove,
+	.remove_new	= bpp_remove,
 };
 
 module_platform_driver(bpp_sbus_driver);
-- 
2.42.0

Re: [PATCH 0/2] parport: Convert to platform remove callback returning void

[Uwe Kleine-König]

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Hello,

[Cc += gregkh]

On Mon, Dec 18, 2023 at 10:05:17PM +0100, Uwe Kleine-König wrote:
> this series converts all drivers below drivers/parport to use
> .remove_new(). See commit 5c5a7680e67b ("platform: Provide a remove
> callback that returns no value") for an extended explanation and the
> eventual goal. The TL;DR; is to make it harder for driver authors to
> leak resources without noticing.
> 
> This is merge window material. The two patches are independent of each
> other, so they could be applied individually.
> 
> Best regards
> Uwe
> 
> Uwe Kleine-König (2):
>   parport: amiga: Convert to platform remove callback returning void
>   parport: sunbpp: Convert to platform remove callback returning void

I got no feedback for these patches since they were sent two months ago
:-\ 

Looking at the last patches to drivers/parport, they were merged by
Greg. Given the patches weren't sent to him, should I resend?

Best regards
Uwe

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

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Re: [PATCH 0/2] parport: Convert to platform remove callback returning void

[Greg Kroah-Hartman]

On Thu, Feb 15, 2024 at 10:22:09PM +0100, Uwe Kleine-König wrote:
> Hello,
> 
> [Cc += gregkh]
> 
> On Mon, Dec 18, 2023 at 10:05:17PM +0100, Uwe Kleine-König wrote:
> > this series converts all drivers below drivers/parport to use
> > .remove_new(). See commit 5c5a7680e67b ("platform: Provide a remove
> > callback that returns no value") for an extended explanation and the
> > eventual goal. The TL;DR; is to make it harder for driver authors to
> > leak resources without noticing.
> > 
> > This is merge window material. The two patches are independent of each
> > other, so they could be applied individually.
> > 
> > Best regards
> > Uwe
> > 
> > Uwe Kleine-König (2):
> >   parport: amiga: Convert to platform remove callback returning void
> >   parport: sunbpp: Convert to platform remove callback returning void
> 
> I got no feedback for these patches since they were sent two months ago
> :-\ 
> 
> Looking at the last patches to drivers/parport, they were merged by
> Greg. Given the patches weren't sent to him, should I resend?

I can just take them directly from here, thanks!

greg k-h