Re: [PATCH V3 2/3] thermal/drivers/cpu_cooling: Unregister with the policy

From: Daniel Lezcano
Date: Wed Jun 26 2019 - 02:02:13 EST



Hi Viresh,


On 26/06/2019 04:58, Viresh Kumar wrote:
> On 25-06-19, 13:32, Daniel Lezcano wrote:
>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
>> index aee024e42618..f07454249fbc 100644
>> --- a/drivers/cpufreq/cpufreq.c
>> +++ b/drivers/cpufreq/cpufreq.c
>> @@ -1379,8 +1379,8 @@ static int cpufreq_online(unsigned int cpu)
>> cpufreq_driver->ready(policy);
>>
>> if (cpufreq_thermal_control_enabled(cpufreq_driver))
>> - policy->cdev = of_cpufreq_cooling_register(policy);
>> -
>> + of_cpufreq_cooling_register(policy);
>> +
>
> We don't need any error checking here anymore ?

There was no error checking initially. This comment and the others below
are for an additional patch IMO, not a change in this one.

>> pr_debug("initialization complete\n");
>>
>> return 0;
>> @@ -1468,10 +1468,8 @@ static int cpufreq_offline(unsigned int cpu)
>> goto unlock;
>> }
>>
>> - if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
>> - cpufreq_cooling_unregister(policy->cdev);
>> - policy->cdev = NULL;
>> - }
>> + if (cpufreq_thermal_control_enabled(cpufreq_driver))
>> + cpufreq_cooling_unregister(policy);
>
> And we unregister unconditionally, even if we failed ? What if this
> routine prints error messages for such an case ?
>>
>> if (cpufreq_driver->stop_cpu)
>> cpufreq_driver->stop_cpu(policy);
>> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
>> index 83486775e593..007c7c6bf845 100644
>> --- a/drivers/thermal/cpu_cooling.c
>> +++ b/drivers/thermal/cpu_cooling.c
>> @@ -78,6 +78,7 @@ struct cpufreq_cooling_device {
>> struct cpufreq_policy *policy;
>> struct list_head node;
>> struct time_in_idle *idle_time;
>> + struct thermal_cooling_device *cdev;
>> };
>>
>> static DEFINE_IDA(cpufreq_ida);
>> @@ -606,6 +607,7 @@ __cpufreq_cooling_register(struct device_node *np,
>> goto remove_ida;
>>
>> cpufreq_cdev->clipped_freq = get_state_freq(cpufreq_cdev, 0);
>> + cpufreq_cdev->cdev = cdev;
>>
>> mutex_lock(&cooling_list_lock);
>> /* Register the notifier for first cpufreq cooling device */
>> @@ -699,18 +701,18 @@ EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
>> *
>> * This interface function unregisters the "thermal-cpufreq-%x" cooling device.
>> */
>> -void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
>> +void cpufreq_cooling_unregister(struct cpufreq_policy *policy)
>> {
>> struct cpufreq_cooling_device *cpufreq_cdev;
>> bool last;
>>
>> - if (!cdev)
>> - return;
>> -
>> - cpufreq_cdev = cdev->devdata;
>> -
>> mutex_lock(&cooling_list_lock);
>> - list_del(&cpufreq_cdev->node);
>> + list_for_each_entry(cpufreq_cdev, &cpufreq_cdev_list, node) {
>> + if (cpufreq_cdev->policy == policy) {
>> + list_del(&cpufreq_cdev->node);
>> + break;
>> + }
>> + }
>
> What if we reach here without a match for the policy ? We shouldn't
> continue and error out, right ? Print an error message as well ?
>


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