[PATCH v5 4/6] PM / devfreq: Use scope-based cleanup helper

[Rafael J. Wysocki]

On Fri, Sep 5, 2025 at 3:25 PM Zihuan Zhang <zhangzihuan at 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 at kylinos.cn>
> ---
>  drivers/devfreq/governor_passive.c | 60 +++++++++++-------------------
>  1 file changed, 22 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
> index 953cf9a1e9f7..5afaea39377e 100644
> --- a/drivers/devfreq/governor_passive.c
> +++ b/drivers/devfreq/governor_passive.c
> @@ -80,24 +80,23 @@ static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
>         struct devfreq_passive_data *p_data =
>                                 (struct devfreq_passive_data *)devfreq->data;
>         struct devfreq_cpu_data *parent_cpu_data;
> -       struct cpufreq_policy *policy;
>         unsigned long cpu, cpu_cur, cpu_min, cpu_max, cpu_percent;
>         unsigned long dev_min, dev_max;
>         unsigned long freq = 0;
>         int ret = 0;
>
>         for_each_online_cpu(cpu) {

I'd rather move the code in this loop to a separate function in the
first place and then do a __free()-based simplification of it.  I'd
suggest doing each step in a separate patch to avoid mistakes.

> -               policy = cpufreq_cpu_get(cpu);
> +               struct cpufreq_policy *policy __free(put_cpufreq_policy) =
> +                       cpufreq_cpu_get(cpu);
> +
>                 if (!policy) {
>                         ret = -EINVAL;
>                         continue;
>                 }
>
>                 parent_cpu_data = get_parent_cpu_data(p_data, policy);
> -               if (!parent_cpu_data) {
> -                       cpufreq_cpu_put(policy);
> +               if (!parent_cpu_data)
>                         continue;
> -               }
>
>                 /* Get target freq via required opps */
>                 cpu_cur = parent_cpu_data->cur_freq * HZ_PER_KHZ;
> @@ -106,7 +105,6 @@ static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
>                                         devfreq->opp_table, &cpu_cur);
>                 if (freq) {
>                         *target_freq = max(freq, *target_freq);
> -                       cpufreq_cpu_put(policy);
>                         continue;
>                 }
>
> @@ -121,7 +119,6 @@ static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
>                 freq = dev_min + mult_frac(dev_max - dev_min, cpu_percent, 100);
>
>                 *target_freq = max(freq, *target_freq);
> -               cpufreq_cpu_put(policy);
>         }
>
>         return ret;
> @@ -255,8 +252,6 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
>                         = (struct devfreq_passive_data *)devfreq->data;
>         struct device *dev = devfreq->dev.parent;
>         struct opp_table *opp_table = NULL;
> -       struct devfreq_cpu_data *parent_cpu_data;
> -       struct cpufreq_policy *policy;
>         struct device *cpu_dev;
>         unsigned int cpu;
>         int ret;
> @@ -273,37 +268,34 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
>         }
>
>         for_each_possible_cpu(cpu) {

And analogously here.  I'd use separate two patches for updating this code.

> -               policy = cpufreq_cpu_get(cpu);
> -               if (!policy) {
> -                       ret = -EPROBE_DEFER;
> -                       goto err;
> -               }
> +               struct cpufreq_policy *policy __free(put_cpufreq_policy) =
> +                       cpufreq_cpu_get(cpu);
>
> -               parent_cpu_data = get_parent_cpu_data(p_data, policy);
> -               if (parent_cpu_data) {
> -                       cpufreq_cpu_put(policy);
> +               if (!policy)
> +                       return -EPROBE_DEFER;
> +
> +               struct devfreq_cpu_data *initial_parent_cpu_data =
> +                       get_parent_cpu_data(p_data, policy);
> +
> +               if (initial_parent_cpu_data)
>                         continue;
> -               }
>
> -               parent_cpu_data = kzalloc(sizeof(*parent_cpu_data),
> -                                               GFP_KERNEL);
> -               if (!parent_cpu_data) {
> -                       ret = -ENOMEM;
> -                       goto err_put_policy;
> -               }
> +               struct devfreq_cpu_data *parent_cpu_data __free(kfree) =
> +                       kzalloc(sizeof(*parent_cpu_data), GFP_KERNEL);
> +
> +               if (!parent_cpu_data)
> +                       return -ENOMEM;
>
>                 cpu_dev = get_cpu_device(cpu);
>                 if (!cpu_dev) {
>                         dev_err(dev, "failed to get cpu device\n");
> -                       ret = -ENODEV;
> -                       goto err_free_cpu_data;
> +                       return -ENODEV;
>                 }
>
>                 opp_table = dev_pm_opp_get_opp_table(cpu_dev);
>                 if (IS_ERR(opp_table)) {
>                         dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
> -                       ret = PTR_ERR(opp_table);
> -                       goto err_free_cpu_data;
> +                       return PTR_ERR(opp_table);
>                 }
>
>                 parent_cpu_data->dev = cpu_dev;
> @@ -313,8 +305,8 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
>                 parent_cpu_data->min_freq = policy->cpuinfo.min_freq;
>                 parent_cpu_data->max_freq = policy->cpuinfo.max_freq;
>
> -               list_add_tail(&parent_cpu_data->node, &p_data->cpu_data_list);
> -               cpufreq_cpu_put(policy);
> +               list_add_tail(&(no_free_ptr(parent_cpu_data)->node,
> +                       &p_data->cpu_data_list);
>         }
>
>         mutex_lock(&devfreq->lock);
> @@ -324,14 +316,6 @@ static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
>                 dev_err(dev, "failed to update the frequency\n");
>
>         return ret;
> -
> -err_free_cpu_data:
> -       kfree(parent_cpu_data);
> -err_put_policy:
> -       cpufreq_cpu_put(policy);
> -err:
> -
> -       return ret;
>  }
>
>  static int devfreq_passive_notifier_call(struct notifier_block *nb,
> --