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

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Message-ID: <20220614022448.pqld3zhqucsfofss@vireshk-i7>
Date:   Tue, 14 Jun 2022 07:54:48 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Lukasz Luba <lukasz.luba@....com>
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 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>

-- 
viresh