[PATCH 00/18] mfd: Convert to platform remove callback returning void

[PATCH 00/18] mfd: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this series converts all platform drivers below drivers/mfd to use
.remove_new(). 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 resource leaks and/or use-after-free bugs.

See commit 5c5a7680e67b ("platform: Provide a remove callback that
returns no value") for an extended explanation and the eventual goal.

All drivers converted here already returned zero unconditionally in
.remove(), so they are converted here trivially.

Best regards
Uwe

Uwe Kleine-König (18):
  mfd: ab8500-sysctrl: Convert to platform remove callback returning
    void
  mfd: cros_ec_dev: Convert to platform remove callback returning void
  mfd: exynos-lpass: Convert to platform remove callback returning void
  mfd: fsl-imx25-tsadc: Convert to platform remove callback returning
    void
  mfd: hi655x-pmic: Convert to platform remove callback returning void
  mfd: intel-lpss-acpi: Convert to platform remove callback returning
    void
  mfd: kempld-core: Convert to platform remove callback returning void
  mfd: mcp-sa11x0: Convert to platform remove callback returning void
  mfd: mxs-lradc: Convert to platform remove callback returning void
  mfd: omap-usb-host: Convert to platform remove callback returning void
  mfd: omap-usb-tll: Convert to platform remove callback returning void
  mfd: pcf50633-adc: Convert to platform remove callback returning void
  mfd: qcom-pm8xxx: Convert to platform remove callback returning void
  mfd: sm501: Convert to platform remove callback returning void
  mfd: stm32-timers: Convert to platform remove callback returning void
  mfd: ti_am335x_tscadc: Convert to platform remove callback returning
    void
  mfd: tps65911-comparator: Convert to platform remove callback
    returning void
  mfd: twl4030-audio: Convert to platform remove callback returning void

 drivers/mfd/ab8500-sysctrl.c      | 6 ++----
 drivers/mfd/cros_ec_dev.c         | 5 ++---
 drivers/mfd/exynos-lpass.c        | 6 ++----
 drivers/mfd/fsl-imx25-tsadc.c     | 6 ++----
 drivers/mfd/hi655x-pmic.c         | 5 ++---
 drivers/mfd/intel-lpss-acpi.c     | 6 ++----
 drivers/mfd/kempld-core.c         | 6 ++----
 drivers/mfd/mcp-sa11x0.c          | 6 ++----
 drivers/mfd/mxs-lradc.c           | 6 ++----
 drivers/mfd/omap-usb-host.c       | 5 ++---
 drivers/mfd/omap-usb-tll.c        | 5 ++---
 drivers/mfd/pcf50633-adc.c        | 6 ++----
 drivers/mfd/qcom-pm8xxx.c         | 6 ++----
 drivers/mfd/sm501.c               | 6 ++----
 drivers/mfd/stm32-timers.c        | 6 ++----
 drivers/mfd/ti_am335x_tscadc.c    | 6 ++----
 drivers/mfd/tps65911-comparator.c | 6 ++----
 drivers/mfd/twl4030-audio.c       | 6 ++----
 18 files changed, 36 insertions(+), 68 deletions(-)

base-commit: 3ff7a5781ceee3befb9224d29cef6e6a4766c5fe
-- 
2.42.0

[PATCH 02/18] mfd: cros_ec_dev: 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/mfd/cros_ec_dev.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 79d393b602bf..603b1cd52785 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -288,13 +288,12 @@ static int ec_device_probe(struct platform_device *pdev)
 	return retval;
 }
 
-static int ec_device_remove(struct platform_device *pdev)
+static void ec_device_remove(struct platform_device *pdev)
 {
 	struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 
 	mfd_remove_devices(ec->dev);
 	device_unregister(&ec->class_dev);
-	return 0;
 }
 
 static const struct platform_device_id cros_ec_id[] = {
@@ -309,7 +308,7 @@ static struct platform_driver cros_ec_dev_driver = {
 	},
 	.id_table = cros_ec_id,
 	.probe = ec_device_probe,
-	.remove = ec_device_remove,
+	.remove_new = ec_device_remove,
 };
 
 static int __init cros_ec_dev_init(void)
-- 
2.42.0

Re: [PATCH 00/18] mfd: Convert to platform remove callback returning void

[Lee Jones]

On Mon, 06 Nov 2023 18:17:09 +0100, Uwe Kleine-König wrote:
> this series converts all platform drivers below drivers/mfd to use
> .remove_new(). 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 resource leaks and/or use-after-free bugs.
> 
> [...]

Applied, thanks!

[01/18] mfd: ab8500-sysctrl: Convert to platform remove callback returning void
        commit: 35cf346f9fa92ceb19c5d2edc4409a7d384da8ee
[02/18] mfd: cros_ec_dev: Convert to platform remove callback returning void
        commit: 981c92a1d65a7ccce2d814c66ff2deecca304672
[03/18] mfd: exynos-lpass: Convert to platform remove callback returning void
        commit: 2d859aa8e081884c0c02d738925cba23a8cfb1b8
[04/18] mfd: fsl-imx25-tsadc: Convert to platform remove callback returning void
        commit: f215b75acc85254a29404b32c871b7ff2ea8da2a
[09/18] mfd: mxs-lradc: Convert to platform remove callback returning void
        commit: beb1f9e6382f59339e118594c94ee6b5ac96f3ec
[10/18] mfd: omap-usb-host: Convert to platform remove callback returning void
        commit: 231927898ae91049aa35d237c556cc216d80e8f7
[11/18] mfd: omap-usb-tll: Convert to platform remove callback returning void
        commit: 83d4e355240147db7597ea1ce64624fcdaaee6ae
[13/18] mfd: qcom-pm8xxx: Convert to platform remove callback returning void
        commit: ae3bcd5b09e35f363aa1744d38f90fda2b40e9ca
[15/18] mfd: stm32-timers: Convert to platform remove callback returning void
        commit: aeebc47f8d479c363e24fba0201ef8dca417fe6e
[18/18] mfd: twl4030-audio: Convert to platform remove callback returning void
        commit: 3716978b584a8baaba16d64c93eb0fed0edcbc3b

--
Lee Jones [李琼斯]

Re: [PATCH 00/18] mfd: Convert to platform remove callback returning void

[Lee Jones]

On Mon, 06 Nov 2023, Uwe Kleine-König wrote:

> Hello,
> 
> this series converts all platform drivers below drivers/mfd to use
> .remove_new(). 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 resource leaks and/or use-after-free bugs.
> 
> See commit 5c5a7680e67b ("platform: Provide a remove callback that
> returns no value") for an extended explanation and the eventual goal.
> 
> All drivers converted here already returned zero unconditionally in
> .remove(), so they are converted here trivially.
> 
> Best regards
> Uwe
> 
> Uwe Kleine-König (18):
>   mfd: ab8500-sysctrl: Convert to platform remove callback returning
>     void
>   mfd: cros_ec_dev: Convert to platform remove callback returning void
>   mfd: exynos-lpass: Convert to platform remove callback returning void
>   mfd: fsl-imx25-tsadc: Convert to platform remove callback returning
>     void
>   mfd: hi655x-pmic: Convert to platform remove callback returning void
>   mfd: intel-lpss-acpi: Convert to platform remove callback returning
>     void
>   mfd: kempld-core: Convert to platform remove callback returning void
>   mfd: mcp-sa11x0: Convert to platform remove callback returning void
>   mfd: mxs-lradc: Convert to platform remove callback returning void
>   mfd: omap-usb-host: Convert to platform remove callback returning void
>   mfd: omap-usb-tll: Convert to platform remove callback returning void
>   mfd: pcf50633-adc: Convert to platform remove callback returning void
>   mfd: qcom-pm8xxx: Convert to platform remove callback returning void
>   mfd: sm501: Convert to platform remove callback returning void
>   mfd: stm32-timers: Convert to platform remove callback returning void
>   mfd: ti_am335x_tscadc: Convert to platform remove callback returning
>     void
>   mfd: tps65911-comparator: Convert to platform remove callback
>     returning void
>   mfd: twl4030-audio: Convert to platform remove callback returning void

Looks like you missed the mailing list on a bunch of these.

I'm going to remove this set for now.

Could you please resubmit it and Cc: LKML?

>  drivers/mfd/ab8500-sysctrl.c      | 6 ++----
>  drivers/mfd/cros_ec_dev.c         | 5 ++---
>  drivers/mfd/exynos-lpass.c        | 6 ++----
>  drivers/mfd/fsl-imx25-tsadc.c     | 6 ++----
>  drivers/mfd/hi655x-pmic.c         | 5 ++---
>  drivers/mfd/intel-lpss-acpi.c     | 6 ++----
>  drivers/mfd/kempld-core.c         | 6 ++----
>  drivers/mfd/mcp-sa11x0.c          | 6 ++----
>  drivers/mfd/mxs-lradc.c           | 6 ++----
>  drivers/mfd/omap-usb-host.c       | 5 ++---
>  drivers/mfd/omap-usb-tll.c        | 5 ++---
>  drivers/mfd/pcf50633-adc.c        | 6 ++----
>  drivers/mfd/qcom-pm8xxx.c         | 6 ++----
>  drivers/mfd/sm501.c               | 6 ++----
>  drivers/mfd/stm32-timers.c        | 6 ++----
>  drivers/mfd/ti_am335x_tscadc.c    | 6 ++----
>  drivers/mfd/tps65911-comparator.c | 6 ++----
>  drivers/mfd/twl4030-audio.c       | 6 ++----
>  18 files changed, 36 insertions(+), 68 deletions(-)
> 
> base-commit: 3ff7a5781ceee3befb9224d29cef6e6a4766c5fe
> -- 
> 2.42.0
> 

-- 
Lee Jones [李琼斯]