linux-kernel - Re: [PATCH v2 01/18] arm64: topology: Use __free(put_cpufreq

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Message-ID: <57016487-0fee-4821-9cd5-d6e5fe80a65d@kylinos.cn>
Date: Wed, 27 Aug 2025 16:55:20 +0800
From: Zihuan Zhang <zhangzihuan@...inos.cn>
To: Ben Horgan <ben.horgan@....com>, "Rafael J . wysocki"
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Subject: Re: [PATCH v2 01/18] arm64: topology: Use __free(put_cpufreq_policy)
 for policy reference

Hi,

在 2025/8/27 16:30, Ben Horgan 写道:
> Hi Zihuan,
>
> On 8/27/25 03:31, Zihuan Zhang wrote:
>> Replace the manual cpufreq_cpu_put() with __free(put_cpufreq_policy)
>> annotation for policy references. This reduces the risk of reference
>> counting mistakes and aligns the code with the latest kernel style.
>>
>> No functional change intended.
>>
>> Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>
>> ---
>>   arch/arm64/kernel/topology.c | 9 +++------
>>   1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
>> index 5d07ee85bdae..e3cb6d54f35b 100644
>> --- a/arch/arm64/kernel/topology.c
>> +++ b/arch/arm64/kernel/topology.c
>> @@ -307,17 +307,16 @@ int arch_freq_get_on_cpu(int cpu)
>>   		 */
>>   		if (!housekeeping_cpu(cpu, HK_TYPE_TICK) ||
>>   		    time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS))) {
>> -			struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
>> +			struct cpufreq_policy *policy __free(put_cpufreq_policy);
> Based on the guidance, in include/linux/cleanup.h, I would expect the
> assignment to be done on this line.
>
> "...the recommendation is to always define and assign variables in one
>   * statement and not group variable definitions at the top of the
>   * function when __free() is used."

The reason I split the assignment into multiple lines is because 
scripts/checkpatch.pl gave a warning about the line being too long.

But if you think a single-line assignment is better, I will modify it 
accordingly.

>>   			int ref_cpu;
>>   
>> +			policy = cpufreq_cpu_get(cpu);
>>   			if (!policy)
>>   				return -EINVAL;
>>   
>>   			if (!cpumask_intersects(policy->related_cpus,
>> -						housekeeping_cpumask(HK_TYPE_TICK))) {
>> -				cpufreq_cpu_put(policy);
>> +						housekeeping_cpumask(HK_TYPE_TICK)))
>>   				return -EOPNOTSUPP;
>> -			}
>>   
>>   			for_each_cpu_wrap(ref_cpu, policy->cpus, cpu + 1) {
>>   				if (ref_cpu == start_cpu) {
>> @@ -329,8 +328,6 @@ int arch_freq_get_on_cpu(int cpu)
>>   					break;
>>   			}
>>   
>> -			cpufreq_cpu_put(policy);
>> -
>>   			if (ref_cpu >= nr_cpu_ids)
>>   				/* No alternative to pull info from */
>>   				return -EAGAIN;
> Thanks,
>
> Ben
>