Thread (25 messages) 25 messages, 3 authors, 2025-09-03

Re: [PATCH v3 09/12] powercap: dtpm_cpu: Use scope-based cleanup helper

From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: 2025-09-03 11:43:31
Also in: dri-devel, imx, intel-gfx, linux-acpi, linux-arm-kernel, linux-omap, linux-pm, lkml

On Mon, Sep 1, 2025 at 10:58 AM Zihuan Zhang [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
---
 drivers/powercap/dtpm_cpu.c | 26 +++++++-------------------
 1 file changed, 7 insertions(+), 19 deletions(-)
diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
index 99390ec1481f..5e18438782f8 100644
--- a/drivers/powercap/dtpm_cpu.c
+++ b/drivers/powercap/dtpm_cpu.c
@@ -144,19 +144,15 @@ 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;
+       struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(dtpm_cpu->cpu);

        if (freq_qos_request_active(&dtpm_cpu->qos_req))
                freq_qos_remove_request(&dtpm_cpu->qos_req);

-       policy = cpufreq_cpu_get(dtpm_cpu->cpu);
Since policy is not needed earlier, you may as well declare it here.
quoted hunk ↗ jump to hunk
-       if (policy) {
+       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 +188,7 @@ 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 cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
        struct em_perf_state *table;
        struct em_perf_domain *pd;
        char name[CPUFREQ_NAME_LEN];
@@ -202,21 +198,16 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
        if (dtpm_cpu)
                return 0;

-       policy = cpufreq_cpu_get(cpu);
Ditto.
quoted hunk ↗ jump to hunk
        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 +230,6 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
        if (ret < 0)
                goto out_dtpm_unregister;

-       cpufreq_cpu_put(policy);
        return 0;

 out_dtpm_unregister:
@@ -251,8 +241,6 @@ 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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