linux-kernel - Re: [PATCH] thermal: cpufreq_cooling: Avoid all cluster using global cooling

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Message-ID: <20220719041448.iyavinsv3jzs3au4@vireshk-i7>
Date:   Tue, 19 Jul 2022 09:44:48 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Di Shen <di.shen@...soc.com>
Cc:     lukasz.luba@....com, amitk@...nel.org, rui.zhang@...el.com,
        amit.kachhap@...il.com, daniel.lezcano@...aro.org,
        rafael@...nel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, xuewen.yan@...soc.com,
        xuewen.yan94@...il.com
Subject: Re: [PATCH] thermal: cpufreq_cooling: Avoid all cluster using global
 cooling_ops

On 18-07-22, 20:24, Di Shen wrote:
> Now, all the cooling device use the globle cpufreq_cooling_ops. When the
> CONFIG_THERMAL_GOV_POWER_ALLOCATOR is enabled, once one cluster init the
> cpufreq_cooling_ops, it would make all cooling device use the power allocator's
> ops. If one's em is error because of the "em_is_sane", it would cause the
> em NULL, but the cooling device's ops is exist, as a result, it would cause
> panic because of the em.
> 
> Add cpufreq_power_cooling_ops to avoid this case.
> 
> Signed-off-by: Di Shen <di.shen@...soc.com>
> Signed-off-by: Xuewen Yan <xuewen.yan@...soc.com>
> ---
>  drivers/thermal/cpufreq_cooling.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
> index b8151d95a806..af5cfb458370 100644
> --- a/drivers/thermal/cpufreq_cooling.c
> +++ b/drivers/thermal/cpufreq_cooling.c
> @@ -493,6 +493,17 @@ static struct thermal_cooling_device_ops cpufreq_cooling_ops = {
>  	.set_cur_state		= cpufreq_set_cur_state,
>  };
>  
> +#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
> +static struct thermal_cooling_device_ops cpufreq_power_cooling_ops = {
> +	.get_max_state		= cpufreq_get_max_state,
> +	.get_cur_state		= cpufreq_get_cur_state,
> +	.set_cur_state		= cpufreq_set_cur_state,
> +	.get_requested_power	= cpufreq_get_requested_power,
> +	.state2power		= cpufreq_state2power,
> +	.power2state		= cpufreq_power2state,
> +};
> +#endif
> +
>  /**
>   * __cpufreq_cooling_register - helper function to create cpufreq cooling device
>   * @np: a valid struct device_node to the cooling device device tree node
> @@ -559,9 +570,7 @@ __cpufreq_cooling_register(struct device_node *np,
>  #ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
>  	if (em_is_sane(cpufreq_cdev, em)) {
>  		cpufreq_cdev->em = em;
> -		cooling_ops->get_requested_power = cpufreq_get_requested_power;
> -		cooling_ops->state2power = cpufreq_state2power;
> -		cooling_ops->power2state = cpufreq_power2state;
> +		cooling_ops = &cpufreq_power_cooling_ops;
>  	} else
>  #endif
>  	if (policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED) {

Please have a look at this patch in linux-next.

commit 6ee324afdf30 ("drivers/thermal/cpufreq_cooling: Use private callback ops for each cooling device")

This already fixes the problem, right ?

-- 
viresh