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Message-ID: <c19b9a8c-bb7d-4d71-89d0-eb98c70a9a85@kylinos.cn>
Date: Tue, 26 Aug 2025 08:29:46 +0800
From: Zihuan Zhang <zhangzihuan@...inos.cn>
To: Gautam Menghani <gautam@...ux.ibm.com>
Cc: "Rafael J . wysocki" <rafael@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>,
Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>,
Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini
<pbonzini@...hat.com>, Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>, Markus Mayer
<mmayer@...adcom.com>, Florian Fainelli <florian.fainelli@...adcom.com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Madhavan Srinivasan <maddy@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>, Krzysztof Kozlowski
<krzk@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>,
Thierry Reding <thierry.reding@...il.com>,
Jonathan Hunter <jonathanh@...dia.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>,
Joonas Lahtinen <joonas.lahtinen@...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>,
Matthias Brugger <matthias.bgg@...il.com>,
AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
zhenglifeng <zhenglifeng1@...wei.com>, "H . Peter Anvin" <hpa@...or.com>,
Zhang Rui <rui.zhang@...el.com>, Len Brown <lenb@...nel.org>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
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, x86@...nel.org, kvm@...r.kernel.org,
linux-acpi@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
linux-samsung-soc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-tegra@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org, imx@...ts.linux.dev,
linux-omap@...r.kernel.org, linux-mediatek@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] cpufreq: use __free() for all cpufreq_cpu_get()
references
在 2025/8/25 19:28, Gautam Menghani 写道:
> On Mon, Aug 25, 2025 at 05:28:33PM +0800, Zihuan Zhang wrote:
>> This patch replaces all remaining uses of cpufreq_cpu_get() with
>> the __free(cpufreq_cpu_put) annotation.
>>
>> Motivation:
>> - Ensures automatic cleanup of policy references when they go out of scope,
>> reducing the risk of forgetting to call cpufreq_cpu_put() on early return
>> or error paths.
>> - Brings the code in line with the latest kernel coding style and best
>> practices for managing reference-counted objects.
>> - No functional changes are introduced; behavior remains the same,
>> but reference counting is now safer and easier to maintain.
>>
>> Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>
>> ---
>> arch/arm64/kernel/topology.c | 9 +++----
>> arch/x86/kvm/x86.c | 10 ++++----
>> drivers/acpi/processor_thermal.c | 13 ++++------
>> drivers/cpufreq/brcmstb-avs-cpufreq.c | 4 +---
>> drivers/cpufreq/cppc_cpufreq.c | 4 +---
>> drivers/cpufreq/intel_pstate.c | 3 +--
>> drivers/cpufreq/longhaul.c | 3 +--
>> drivers/cpufreq/mediatek-cpufreq.c | 6 ++---
>> drivers/cpufreq/powernv-cpufreq.c | 6 ++---
>> drivers/cpufreq/s5pv210-cpufreq.c | 3 +--
>> drivers/cpufreq/tegra186-cpufreq.c | 3 +--
>> drivers/devfreq/governor_passive.c | 19 ++++-----------
>> drivers/gpu/drm/i915/gt/intel_llc.c | 3 +--
>> drivers/macintosh/windfarm_cpufreq_clamp.c | 4 +---
>> drivers/powercap/dtpm_cpu.c | 24 ++++++-------------
>> drivers/thermal/imx_thermal.c | 7 ++----
>> .../ti-soc-thermal/ti-thermal-common.c | 5 +---
>> kernel/power/energy_model.c | 7 ++----
>> 18 files changed, 40 insertions(+), 93 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);
>> 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;
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index a1c49bc681c4..2a825f4ec701 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -9492,16 +9492,14 @@ static void kvm_timer_init(void)
>> max_tsc_khz = tsc_khz;
>>
>> if (IS_ENABLED(CONFIG_CPU_FREQ)) {
>> - struct cpufreq_policy *policy;
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy);
>> int cpu;
>>
>> cpu = get_cpu();
>> policy = cpufreq_cpu_get(cpu);
>> - if (policy) {
>> - if (policy->cpuinfo.max_freq)
>> - max_tsc_khz = policy->cpuinfo.max_freq;
>> - cpufreq_cpu_put(policy);
>> - }
>> + if (policy && policy->cpuinfo.max_freq)
>> + max_tsc_khz = policy->cpuinfo.max_freq;
>> +
>> put_cpu();
>> }
>> cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
>> diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
>> index 1219adb11ab9..8367a81c4842 100644
>> --- a/drivers/acpi/processor_thermal.c
>> +++ b/drivers/acpi/processor_thermal.c
>> @@ -64,17 +64,14 @@ static int phys_package_first_cpu(int cpu)
>>
>> static int cpu_has_cpufreq(unsigned int cpu)
>> {
>> - struct cpufreq_policy *policy;
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy);
>>
>> 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)
>> @@ -95,7 +92,7 @@ static int cpufreq_get_cur_state(unsigned int cpu)
>>
>> static int cpufreq_set_cur_state(unsigned int cpu, int state)
>> {
>> - struct cpufreq_policy *policy;
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy);
>> struct acpi_processor *pr;
>> unsigned long max_freq;
>> int i, ret;
>> @@ -127,8 +124,6 @@ static int cpufreq_set_cur_state(unsigned int cpu, int state)
>> max_freq = (policy->cpuinfo.max_freq *
>> (100 - reduction_step(i) * cpufreq_thermal_reduction_pctg)) / 100;
>>
>> - cpufreq_cpu_put(policy);
>> -
>> ret = freq_qos_update_request(&pr->thermal_req, max_freq);
>> if (ret < 0) {
>> pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
>> diff --git a/drivers/cpufreq/brcmstb-avs-cpufreq.c b/drivers/cpufreq/brcmstb-avs-cpufreq.c
>> index 5940d262374f..71450cca8e9f 100644
>> --- a/drivers/cpufreq/brcmstb-avs-cpufreq.c
>> +++ b/drivers/cpufreq/brcmstb-avs-cpufreq.c
>> @@ -480,7 +480,7 @@ static bool brcm_avs_is_firmware_loaded(struct private_data *priv)
>>
>> static unsigned int brcm_avs_cpufreq_get(unsigned int cpu)
>> {
>> - struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
>> struct private_data *priv;
>>
>> if (!policy)
>> @@ -488,8 +488,6 @@ static unsigned int brcm_avs_cpufreq_get(unsigned int cpu)
>>
>> priv = policy->driver_data;
>>
>> - cpufreq_cpu_put(policy);
>> -
>> return brcm_avs_get_frequency(priv->base);
>> }
>>
>> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
>> index 4a17162a392d..7183754b1f31 100644
>> --- a/drivers/cpufreq/cppc_cpufreq.c
>> +++ b/drivers/cpufreq/cppc_cpufreq.c
>> @@ -726,7 +726,7 @@ static int cppc_get_perf_ctrs_sample(int cpu,
>> static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
>> {
>> struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
>> - struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
>> struct cppc_cpudata *cpu_data;
>> u64 delivered_perf;
>> int ret;
>> @@ -736,8 +736,6 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
>>
>> cpu_data = policy->driver_data;
>>
>> - cpufreq_cpu_put(policy);
>> -
>> ret = cppc_get_perf_ctrs_sample(cpu, &fb_ctrs_t0, &fb_ctrs_t1);
>> if (ret) {
>> if (ret == -EFAULT)
>> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
>> index f366d35c5840..fb962140af56 100644
>> --- a/drivers/cpufreq/intel_pstate.c
>> +++ b/drivers/cpufreq/intel_pstate.c
>> @@ -1698,7 +1698,7 @@ static ssize_t store_no_turbo(struct kobject *a, struct kobj_attribute *b,
>> static void update_qos_request(enum freq_qos_req_type type)
>> {
>> struct freq_qos_request *req;
>> - struct cpufreq_policy *policy;
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy);
>> int i;
>>
>> for_each_possible_cpu(i) {
>> @@ -1710,7 +1710,6 @@ static void update_qos_request(enum freq_qos_req_type type)
>> continue;
>>
>> req = policy->driver_data;
>> - cpufreq_cpu_put(policy);
>>
>> if (!req)
>> continue;
>> diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
>> index ba0e08c8486a..ae5596919671 100644
>> --- a/drivers/cpufreq/longhaul.c
>> +++ b/drivers/cpufreq/longhaul.c
>> @@ -950,7 +950,7 @@ static int __init longhaul_init(void)
>>
>> static void __exit longhaul_exit(void)
>> {
>> - struct cpufreq_policy *policy = cpufreq_cpu_get(0);
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(0);
>> int i;
>>
>> for (i = 0; i < numscales; i++) {
>> @@ -968,7 +968,6 @@ static void __exit longhaul_exit(void)
>> }
>> }
>>
>> - cpufreq_cpu_put(policy);
>> cpufreq_unregister_driver(&longhaul_driver);
>> kfree(longhaul_table);
>> }
>> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
>> index f3f02c4b6888..1fae060e16d9 100644
>> --- a/drivers/cpufreq/mediatek-cpufreq.c
>> +++ b/drivers/cpufreq/mediatek-cpufreq.c
>> @@ -320,7 +320,7 @@ static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
>> struct dev_pm_opp *new_opp;
>> struct mtk_cpu_dvfs_info *info;
>> unsigned long freq, volt;
>> - struct cpufreq_policy *policy;
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy);
>> int ret = 0;
>>
>> info = container_of(nb, struct mtk_cpu_dvfs_info, opp_nb);
>> @@ -354,11 +354,9 @@ static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
>>
>> dev_pm_opp_put(new_opp);
>> policy = cpufreq_cpu_get(info->opp_cpu);
>> - if (policy) {
>> + if (policy)
>> cpufreq_driver_target(policy, freq / 1000,
>> CPUFREQ_RELATION_L);
>> - cpufreq_cpu_put(policy);
>> - }
>> }
>> }
>>
>> diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
>> index 7d9a5f656de8..ea9d78bbeb38 100644
>> --- a/drivers/cpufreq/powernv-cpufreq.c
>> +++ b/drivers/cpufreq/powernv-cpufreq.c
>> @@ -892,7 +892,7 @@ static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
>> unsigned long action, void *unused)
>> {
>> int cpu;
>> - struct cpufreq_policy *cpu_policy;
>> + struct cpufreq_policy *policy __free(put_cpufreq_policy);
> There's a typo here. I got a compile error because of wrong variable name.
>
> Thanks,
> Gautam
Sorry about that.
Although we did compile-test it, some configs are not enabled by default
so we missed this issue. I’ll fix it in the next version.
Thanks for catching this!
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