Re: [PATCH] perf/smmuv3: Remove the leftover put_cpu() in error path

[Hanjun Guo]

On 2019/12/10 22:10, Will Deacon wrote:
> On Tue, Dec 10, 2019 at 09:55:28PM +0800, Hanjun Guo wrote:
>> On 2019/12/10 21:24, Will Deacon wrote:
>>> On Tue, Dec 10, 2019 at 06:46:24PM +0800, Hanjun Guo wrote:
>>>> In smmu_pmu_probe(), there is put_cpu() in the error path,
>>>> which is wrong because we use raw_smp_processor_id() to
>>>> get the cpu ID, not get_cpu(), remove it.
>>>>
>>>> Signed-off-by: Hanjun Guo <guohanjun@xxxxxxxxxx>
>>>> ---
>>>>  drivers/perf/arm_smmuv3_pmu.c | 1 -
>>>>  1 file changed, 1 deletion(-)
>>>>
>>>> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
>>>> index 773128f..fd1d46a 100644
>>>> --- a/drivers/perf/arm_smmuv3_pmu.c
>>>> +++ b/drivers/perf/arm_smmuv3_pmu.c
>>>> @@ -834,7 +834,6 @@ static int smmu_pmu_probe(struct platform_device *pdev)
>>>>  out_unregister:
>>>>  	cpuhp_state_remove_instance_nocalls(cpuhp_state_num, &smmu_pmu->node);
>>>>  out_cpuhp_err:
>>>> -	put_cpu();
>>>>  	return err;
>>>
>>> Can we kill 'out_cpuhp_err' altogether then and just return err if we fail
>>> to add the hotplug instance?
>>
>> Makes sense, but I think we can go further to kill both 'out_cpuhp_err' and
>> 'out_register' as below [1], what do you think?
> 
> Although that's functionally correct, I'd prefer to keep out_unregister(),
> since it acts as good reminder to anybody extending this function in future
> that they need to unregister the hotplug instance on failure.

OK, I will add Robin's ACK and resend.

Thanks
Hanjun