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Message-ID: <CAJZ5v0hirWzWZiLbAXPWB58SQv3CAW95iHLnsqs=i2twVCcmwg@mail.gmail.com>
Date: Wed, 3 Sep 2025 15:45:17 +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>,
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 v4 07/10] powercap: dtpm_cpu: Use scope-based cleanup helper
On Wed, Sep 3, 2025 at 3:18 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/powercap/dtpm_cpu.c | 30 +++++++++++-------------------
> 1 file changed, 11 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
> index 99390ec1481f..f76594185fa2 100644
> --- a/drivers/powercap/dtpm_cpu.c
> +++ b/drivers/powercap/dtpm_cpu.c
> @@ -144,19 +144,17 @@ static int update_pd_power_uw(struct dtpm *dtpm)
> static void pd_release(struct dtpm *dtpm)
> {
> struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
> - struct cpufreq_policy *policy;
>
> if (freq_qos_request_active(&dtpm_cpu->qos_req))
> freq_qos_remove_request(&dtpm_cpu->qos_req);
>
> - policy = cpufreq_cpu_get(dtpm_cpu->cpu);
> - if (policy) {
> + struct cpufreq_policy *policy __free(put_cpufreq_policy) =
> + cpufreq_cpu_get(dtpm_cpu->cpu);
> +
> + if (policy)
> for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)
> per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;
>
> - cpufreq_cpu_put(policy);
> - }
> -
> kfree(dtpm_cpu);
> }
>
> @@ -192,7 +190,6 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
> static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
> {
> struct dtpm_cpu *dtpm_cpu;
> - struct cpufreq_policy *policy;
> struct em_perf_state *table;
> struct em_perf_domain *pd;
> char name[CPUFREQ_NAME_LEN];
> @@ -202,21 +199,19 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
> if (dtpm_cpu)
> return 0;
>
> - policy = cpufreq_cpu_get(cpu);
> + struct cpufreq_policy *policy __free(put_cpufreq_policy) =
> + cpufreq_cpu_get(cpu);
> +
> if (!policy)
> return 0;
>
> pd = em_cpu_get(cpu);
> - if (!pd || em_is_artificial(pd)) {
> - ret = -EINVAL;
> - goto release_policy;
> - }
> + if (!pd || em_is_artificial(pd))
> + return -EINVAL;
>
> dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
> - if (!dtpm_cpu) {
> - ret = -ENOMEM;
> - goto release_policy;
> - }
> + if (!dtpm_cpu)
> + return -ENOMEM;
>
> dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
> dtpm_cpu->cpu = cpu;
> @@ -239,7 +234,6 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
> if (ret < 0)
> goto out_dtpm_unregister;
So this change kind of goes against another recommendation given in cleanup.h:
* Lastly, given that the benefit of cleanup helpers is removal of
* "goto", and that the "goto" statement can jump between scopes, the
* expectation is that usage of "goto" and cleanup helpers is never
* mixed in the same function. I.e. for a given routine, convert all
* resources that need a "goto" cleanup to scope-based cleanup, or
* convert none of them.
>
> - cpufreq_cpu_put(policy);
> return 0;
>
> out_dtpm_unregister:
> @@ -251,8 +245,6 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
> per_cpu(dtpm_per_cpu, cpu) = NULL;
> kfree(dtpm_cpu);
>
> -release_policy:
> - cpufreq_cpu_put(policy);
> return ret;
> }
>
> --
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