linux-kernel - Re: [PATCH v2 1/4] thermal: cpufreq_cooling: Use private callback ops for each cooling device

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Date:   Tue, 14 Jun 2022 10:50:53 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        daniel.lezcano@...aro.org, amitk@...nel.org, rui.zhang@...el.com,
        rafael@...nel.org, dietmar.eggemann@....com, rostedt@...dmis.org,
        mingo@...hat.com
Subject: Re: [PATCH v2 1/4] thermal: cpufreq_cooling: Use private callback ops
 for each cooling device



On 6/14/22 03:24, Viresh Kumar wrote:
> On 13-06-22, 13:43, Lukasz Luba wrote:
>> It is very unlikely that one CPU cluster would have the EM and some other
>> won't have it (because EM registration failed or DT lacks needed entry).
>> Although, we should avoid modifying global variable with callbacks anyway.
>> Redesign this and add safety for such situation.
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
>> ---
>>   drivers/thermal/cpufreq_cooling.c | 15 ++++++---------
>>   1 file changed, 6 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
>> index b8151d95a806..ad8b86f5281b 100644
>> --- a/drivers/thermal/cpufreq_cooling.c
>> +++ b/drivers/thermal/cpufreq_cooling.c
>> @@ -59,6 +59,7 @@ struct time_in_idle {
>>    * @cdev: thermal_cooling_device pointer to keep track of the
>>    *	registered cooling device.
>>    * @policy: cpufreq policy.
>> + * @cooling_ops: cpufreq callbacks to thermal cooling device ops
>>    * @idle_time: idle time stats
>>    * @qos_req: PM QoS contraint to apply
>>    *
>> @@ -71,6 +72,7 @@ struct cpufreq_cooling_device {
>>   	unsigned int max_level;
>>   	struct em_perf_domain *em;
>>   	struct cpufreq_policy *policy;
>> +	struct thermal_cooling_device_ops cooling_ops;
>>   #ifndef CONFIG_SMP
>>   	struct time_in_idle *idle_time;
>>   #endif
>> @@ -485,14 +487,6 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
>>   	return ret;
>>   }
>>   
>> -/* Bind cpufreq callbacks to thermal cooling device ops */
>> -
>> -static struct thermal_cooling_device_ops cpufreq_cooling_ops = {
>> -	.get_max_state		= cpufreq_get_max_state,
>> -	.get_cur_state		= cpufreq_get_cur_state,
>> -	.set_cur_state		= cpufreq_set_cur_state,
>> -};
>> -
>>   /**
>>    * __cpufreq_cooling_register - helper function to create cpufreq cooling device
>>    * @np: a valid struct device_node to the cooling device device tree node
>> @@ -554,7 +548,10 @@ __cpufreq_cooling_register(struct device_node *np,
>>   	/* max_level is an index, not a counter */
>>   	cpufreq_cdev->max_level = i - 1;
>>   
>> -	cooling_ops = &cpufreq_cooling_ops;
>> +	cooling_ops = &cpufreq_cdev->cooling_ops;
>> +	cooling_ops->get_max_state = cpufreq_get_max_state;
>> +	cooling_ops->get_cur_state = cpufreq_get_cur_state;
>> +	cooling_ops->set_cur_state = cpufreq_set_cur_state;
>>   
>>   #ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
>>   	if (em_is_sane(cpufreq_cdev, em)) {
> 
> Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
> 


Thank you Viresh for the ACK!