Messages in this thread |  | | Date | Thu, 4 Sep 2025 18:37:54 +0800 | | Subject | Re: [PATCH v4 07/10] powercap: dtpm_cpu: Use scope-based cleanup helper | | From | Zihuan Zhang <> |
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在 2025/9/3 21:45, Rafael J. Wysocki 写道: > On Wed, Sep 3, 2025 at 3:18 PM Zihuan Zhang <zhangzihuan@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@kylinos.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.
Should I replace all the memory allocation cleanups here with `__free`? That would allow us to drop all the `goto`s, but since this function has quite a few of them, I’m concerned it might introduce new issues. What’s your recommendation?
Thanks!
>> - 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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