Re: [PATCH v4 02/10] ACPI: processor: thermal: Use scope-based cleanup helper

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Wed, 3 Sep 2025 15:23:31 +0200
"Rafael J. Wysocki" <rafael@kernel.org> wrote:

> On Wed, Sep 3, 2025 at 3:18 PM Zihuan Zhang <zhangzihuan@kylinos.cn> 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@kylinos.cn>
> > ---
> >  drivers/acpi/processor_thermal.c | 37 ++++++++++++++++++--------------
> >  1 file changed, 21 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
> > index 1219adb11ab9..5043f17d27b7 100644
> > --- a/drivers/acpi/processor_thermal.c
> > +++ b/drivers/acpi/processor_thermal.c
> > @@ -62,19 +62,14 @@ static int phys_package_first_cpu(int cpu)
> >         return 0;
> >  }
> >
> > -static int cpu_has_cpufreq(unsigned int cpu)
> > +static bool cpu_has_cpufreq(unsigned int cpu)
> >  {
> > -       struct cpufreq_policy *policy;
> > +       struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);

I'd put the order back as it was.  See docs in cleanup.h, it is fine to
declare local variables inline if they are being use with __free()

That way if the simple check on acpi_process_cpu_freq_init fails no
get needs to occur.

So something like

static bool cpu_has_cpufreq(unsigned int cpu)
{
	if (!acpi_processor_cpufreq_init)
                 return 0;

	struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);

	return policy != NULL; //Personally I find !! on a pointer a bit weird :)
}

> >
> >         if (!acpi_processor_cpufreq_init)
> >                 return 0;
> >
> > -       policy = cpufreq_cpu_get(cpu);
> > -       if (policy) {
> > -               cpufreq_cpu_put(policy);
> > -               return 1;
> > -       }
> > -       return 0;
> > +       return !!policy;
> >  }
> >
> >  static int cpufreq_get_max_state(unsigned int cpu)
> > @@ -93,9 +88,23 @@ static int cpufreq_get_cur_state(unsigned int cpu)
> >         return reduction_step(cpu);
> >  }
> >
> > +static long long cpufreq_get_max_freq(unsigned int cpu)
> > +{
> > +       long long max_freq;
> > +       struct cpufreq_policy *policy __free(put_cpufreq_policy) =
> > +               cpufreq_cpu_get(cpu);

Format consistently.  If you are going to wrap to 80 chars here
then do it for the cpu_has_cpufreq() line that is identical to this.

> > +
> > +       if (!policy)
> > +               return -EINVAL;
> > +
> > +       max_freq = (policy->cpuinfo.max_freq *
> > +               (100 - reduction_step(cpu) * cpufreq_thermal_reduction_pctg)) / 100;
> > +
> > +       return max_freq;
> > +}
> > +
> >  static int cpufreq_set_cur_state(unsigned int cpu, int state)
> >  {
> > -       struct cpufreq_policy *policy;
> >         struct acpi_processor *pr;
> >         unsigned long max_freq;
> >         int i, ret;
> > @@ -120,14 +129,10 @@ static int cpufreq_set_cur_state(unsigned int cpu, int state)
> >                 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
> >                         continue;
> >
> > -               policy = cpufreq_cpu_get(i);
> > -               if (!policy)
> > -                       return -EINVAL;
> > -
> > -               max_freq = (policy->cpuinfo.max_freq *
> > -                           (100 - reduction_step(i) * cpufreq_thermal_reduction_pctg)) / 100;
> > +               max_freq = cpufreq_get_max_freq(cpu);
> >
> > -               cpufreq_cpu_put(policy);
> > +               if (max_freq == -EINVAL)
> > +                       return -EINVAL;  
> 
> Please also move the code below to the new function so it does not
> need to return a value.
> 
> >
> >                 ret = freq_qos_update_request(&pr->thermal_req, max_freq);
> >                 if (ret < 0) {
> > --  
>