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Message-ID: <CAJZ5v0jvskvxgUhxKJLN89A+s7Mruz1_tewHZfKgC7sUGLi9cw@mail.gmail.com>
Date: Fri, 5 Sep 2025 21:39:52 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Zihuan Zhang <zhangzihuan@...inos.cn>
Cc: "Rafael J . wysocki" <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>,
Jonathan Cameron <jonathan.cameron@...wei.com>, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>, Michael Ellerman <mpe@...erman.id.au>,
Krzysztof Kozlowski <krzk@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>,
Thierry Reding <thierry.reding@...il.com>, MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>, Chanwoo Choi <cw00.choi@...sung.com>,
Jani Nikula <jani.nikula@...ux.intel.com>, Rodrigo Vivi <rodrigo.vivi@...el.com>,
Tvrtko Ursulin <tursulin@...ulin.net>, David Airlie <airlied@...il.com>,
Simona Vetter <simona@...ll.ch>, Daniel Lezcano <daniel.lezcano@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>, Shawn Guo <shawnguo@...nel.org>,
Eduardo Valentin <edubezval@...il.com>, Keerthy <j-keerthy@...com>, Ben Horgan <ben.horgan@....com>,
zhenglifeng <zhenglifeng1@...wei.com>, Zhang Rui <rui.zhang@...el.com>,
Len Brown <lenb@...nel.org>, Lukasz Luba <lukasz.luba@....com>,
Pengutronix Kernel Team <kernel@...gutronix.de>, Beata Michalska <beata.michalska@....com>,
Fabio Estevam <festevam@...il.com>, Pavel Machek <pavel@...nel.org>, Sumit Gupta <sumitg@...dia.com>,
Prasanna Kumar T S M <ptsm@...ux.microsoft.com>, Sudeep Holla <sudeep.holla@....com>,
Yicong Yang <yangyicong@...ilicon.com>, linux-pm@...r.kernel.org,
linux-acpi@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
linux-arm-kernel@...ts.infradead.org, intel-gfx@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org, imx@...ts.linux.dev,
linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 4/6] PM / devfreq: Use scope-based cleanup helper
On Fri, Sep 5, 2025 at 3:25 PM Zihuan Zhang <zhangzihuan@...inos.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@...inos.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,
> --
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