Re: [PATCH v2 11/11] thermal: core: Manage thermal_governor_lock using a mutex guard

[Lukasz Luba <lukasz.luba@arm.com>]

On 10/10/24 23:22, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Switch over the thermal core to using a mutex guard for
> thermal_governor_lock management.
> 
> No intentional functional impact.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> 
> This is a resend of
> 
> https://lore.kernel.org/linux-pm/863177860.0ifERbkFSE@rjwysocki.net/
> 
> ---
>   drivers/thermal/thermal_core.c |   40 +++++++++++++---------------------------
>   1 file changed, 13 insertions(+), 27 deletions(-)
> 
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -124,7 +124,7 @@ int thermal_register_governor(struct the
>   	if (!governor)
>   		return -EINVAL;
>   
> -	mutex_lock(&thermal_governor_lock);
> +	guard(mutex)(&thermal_governor_lock);
>   
>   	err = -EBUSY;
>   	if (!__find_governor(governor->name)) {
> @@ -163,8 +163,6 @@ int thermal_register_governor(struct the
>   		}
>   	}
>   
> -	mutex_unlock(&thermal_governor_lock);
> -
>   	return err;
>   }
>   
> @@ -175,10 +173,10 @@ void thermal_unregister_governor(struct
>   	if (!governor)
>   		return;
>   
> -	mutex_lock(&thermal_governor_lock);
> +	guard(mutex)(&thermal_governor_lock);
>   
>   	if (!__find_governor(governor->name))
> -		goto exit;
> +		return;
>   
>   	list_del(&governor->governor_list);
>   
> @@ -189,9 +187,6 @@ void thermal_unregister_governor(struct
>   				 THERMAL_NAME_LENGTH))
>   			thermal_set_governor(pos, NULL);
>   	}
> -
> -exit:
> -	mutex_unlock(&thermal_governor_lock);
>   }
>   
>   int thermal_zone_device_set_policy(struct thermal_zone_device *tz,
> @@ -200,16 +195,13 @@ int thermal_zone_device_set_policy(struc
>   	struct thermal_governor *gov;
>   	int ret = -EINVAL;
>   
> -	mutex_lock(&thermal_governor_lock);
> -
> +	guard(mutex)(&thermal_governor_lock);
>   	guard(thermal_zone)(tz);
>   
>   	gov = __find_governor(strim(policy));
>   	if (gov)
>   		ret = thermal_set_governor(tz, gov);
>   
> -	mutex_unlock(&thermal_governor_lock);
> -
>   	thermal_notify_tz_gov_change(tz, policy);
>   
>   	return ret;
> @@ -220,15 +212,13 @@ int thermal_build_list_of_policies(char
>   	struct thermal_governor *pos;
>   	ssize_t count = 0;
>   
> -	mutex_lock(&thermal_governor_lock);
> +	guard(mutex)(&thermal_governor_lock);
>   
>   	list_for_each_entry(pos, &thermal_governor_list, governor_list) {
>   		count += sysfs_emit_at(buf, count, "%s ", pos->name);
>   	}
>   	count += sysfs_emit_at(buf, count, "\n");
>   
> -	mutex_unlock(&thermal_governor_lock);
> -
>   	return count;
>   }
>   
> @@ -668,17 +658,18 @@ int for_each_thermal_governor(int (*cb)(
>   			      void *data)
>   {
>   	struct thermal_governor *gov;
> -	int ret = 0;
>   
> -	mutex_lock(&thermal_governor_lock);
> +	guard(mutex)(&thermal_governor_lock);
> +
>   	list_for_each_entry(gov, &thermal_governor_list, governor_list) {
> +		int ret;
> +
>   		ret = cb(gov, data);
>   		if (ret)
> -			break;
> +			return ret;
>   	}
> -	mutex_unlock(&thermal_governor_lock);
>   
> -	return ret;
> +	return 0;
>   }
>   
>   int for_each_thermal_cooling_device(int (*cb)(struct thermal_cooling_device *,
> @@ -1346,20 +1337,15 @@ EXPORT_SYMBOL_GPL(thermal_zone_get_crit_
>   static int thermal_zone_init_governor(struct thermal_zone_device *tz)
>   {
>   	struct thermal_governor *governor;
> -	int ret;
>   
> -	mutex_lock(&thermal_governor_lock);
> +	guard(mutex)(&thermal_governor_lock);
>   
>   	if (tz->tzp)
>   		governor = __find_governor(tz->tzp->governor_name);
>   	else
>   		governor = def_governor;
>   
> -	ret = thermal_set_governor(tz, governor);
> -
> -	mutex_unlock(&thermal_governor_lock);
> -
> -	return ret;
> +	return thermal_set_governor(tz, governor);
>   }
>   
>   static void thermal_zone_init_complete(struct thermal_zone_device *tz)
> 
> 
> 

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>