2023-12-15 14:04:06

by Uwe Kleine-König

Subject: [PATCH 16/18] perf: qcom_l2: Convert to platform remove callback returning void

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 <[email protected]>
---
drivers/perf/qcom_l2_pmu.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/qcom_l2_pmu.c b/drivers/perf/qcom_l2_pmu.c
index 3f9a98c17a89..148df5ae8ef8 100644
--- a/drivers/perf/qcom_l2_pmu.c
+++ b/drivers/perf/qcom_l2_pmu.c
@@ -965,7 +965,7 @@ static int l2_cache_pmu_probe(struct platform_device *pdev)
return err;
}

-static int l2_cache_pmu_remove(struct platform_device *pdev)
+static void l2_cache_pmu_remove(struct platform_device *pdev)
{
struct l2cache_pmu *l2cache_pmu =
to_l2cache_pmu(platform_get_drvdata(pdev));
@@ -973,7 +973,6 @@ static int l2_cache_pmu_remove(struct platform_device *pdev)
perf_pmu_unregister(&l2cache_pmu->pmu);
cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
&l2cache_pmu->node);
- return 0;
}

static struct platform_driver l2_cache_pmu_driver = {
@@ -983,7 +982,7 @@ static struct platform_driver l2_cache_pmu_driver = {
.suppress_bind_attrs = true,
},
.probe = l2_cache_pmu_probe,
- .remove = l2_cache_pmu_remove,
+ .remove_new = l2_cache_pmu_remove,
};

static int __init register_l2_cache_pmu_driver(void)
--
2.42.0

2023-12-15 23:30:17

by Konrad Dybcio

Subject: Re: [PATCH 16/18] perf: qcom_l2: Convert to platform remove callback returning void

On 15.12.2023 14:59, 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 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 <[email protected]>
> ---
Reviewed-by: Konrad Dybcio <[email protected]>

Konrad