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

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Message-ID: <5081cf6c-6e2a-4a6f-841a-e4a21c35cb21@kylinos.cn>
Date: Wed, 27 Aug 2025 17:21:50 +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 17:12, Ben Horgan 写道:
> Hi Zihuan,
>
> On 8/27/25 09:55, Zihuan Zhang wrote:
>> 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.
> My preference, for what it's worth, would be to keep it one statement
> and split the line after the =.


Okay,  I will update it that way. Thanks.

>>>>                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
>>>
> Thanks,
>
> Ben
>