Re: [PATCH v3 4/5] amba: Make the remove callback return void

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

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Hello,

On Tue, Jan 26, 2021 at 05:08:40PM +0000, Suzuki K Poulose wrote:
> On 1/26/21 4:58 PM, Uwe Kleine-König wrote:
> > All amba drivers return 0 in their remove callback. Together with the
> > driver core ignoring the return value anyhow, it doesn't make sense to
> > return a value here.
> > 
> > Change the remove prototype to return void, which makes it explicit that
> > returning an error value doesn't work as expected. This simplifies changing
> > the core remove callback to return void, too.
> > 
> > Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> > Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> > Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory
> > Acked-by: Mark Brown <broonie@kernel.org>
>  > Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Acked-by: Linus Walleij <linus.walleij@linaro.org>
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> 
> 
> >   drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 +---
> 
> You are most likely to have a conflict for the above file, with what is
> in coresight/next. It should be easy to resolve.

I'm surprised to see that the remove callback introduced in 2952ecf5df33
("coresight: etm4x: Refactor probing routine") has an __exit annotation.

With .suppress_bind_attrs = true you don't need a remove callback at
all. (And without .suppress_bind_attrs = true the remove callback must
have no __exit annotation.)

This make me looking at commit 45fe7befe0db ("coresight: remove broken
__exit annotations") by Arnd. Unless I miss something the better change
would have been to remove the unused remove callbacks instead of dropping
their __exit annotation?!

Anyhow, my conflict resolution looks as follows:

diff --cc drivers/hwtracing/coresight/coresight-etm4x-core.c
index 82787cba537d,473ab7480a36..000000000000
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@@ -1703,6 -1903,28 +1903,27 @@@ static int __exit etm4_remove_dev(struc
  	cpus_read_unlock();
  
  	coresight_unregister(drvdata->csdev);
+ 
+ 	return 0;
+ }
+ 
 -static int __exit etm4_remove_amba(struct amba_device *adev)
++static void __exit etm4_remove_amba(struct amba_device *adev)
+ {
+ 	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+ 
+ 	if (drvdata)
 -		return etm4_remove_dev(drvdata);
 -	return 0;
++		etm4_remove_dev(drvdata);
+ }
+ 
+ static int __exit etm4_remove_platform_dev(struct platform_device *pdev)
+ {
+ 	int ret = 0;
+ 	struct etmv4_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
+ 
+ 	if (drvdata)
+ 		ret = etm4_remove_dev(drvdata);
+ 	pm_runtime_disable(&pdev->dev);
+ 	return ret;
  }
  
  static const struct amba_id etm4_ids[] = {

If this series should make it in for 5.12 we probably need an immutable
branch between hwtracing and amba.

> Otherwise, the changes look good for the drivers/hwtracing/coresight/*
> 
> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Thanks
Uwe

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

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