linux-kernel - Re: [PATCH v2 03/11] thermal: core: Separate code running under thermal_list

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Message-ID: <d62d6745-678f-4168-964e-6c8366c128da@arm.com>
Date: Tue, 22 Oct 2024 22:09:11 +0100
From: Lukasz Luba <lukasz.luba@....com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: LKML <linux-kernel@...r.kernel.org>, Linux PM <linux-pm@...r.kernel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>, Zhang Rui <rui.zhang@...el.com>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: Re: [PATCH v2 03/11] thermal: core: Separate code running under
 thermal_list_lock



On 10/10/24 23:09, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> To prepare for a subsequent change that will switch over the thermal
> core to using a mutex guard for thermal_list_lock management, move the
> code running under thermal_list_lock during the initialization and
> unregistration of cooling devices into separate functions.
> 
> While at it, drop some comments that do not add value.
> 
> No intentional functional impact.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> 
> This is a resend of
> 
> https://lore.kernel.org/linux-pm/1822468.VLH7GnMWUR@rjwysocki.net/
> 
> ---
>   drivers/thermal/thermal_core.c |   64 +++++++++++++++++++++++------------------
>   1 file changed, 36 insertions(+), 28 deletions(-)
> 
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -965,6 +965,20 @@ static void thermal_zone_cdev_bind(struc
>   		__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
>   }
>   
> +static void thermal_cooling_device_init_complete(struct thermal_cooling_device *cdev)
> +{
> +	struct thermal_zone_device *tz;
> +
> +	mutex_lock(&thermal_list_lock);
> +
> +	list_add(&cdev->node, &thermal_cdev_list);
> +
> +	list_for_each_entry(tz, &thermal_tz_list, node)
> +		thermal_zone_cdev_bind(tz, cdev);
> +
> +	mutex_unlock(&thermal_list_lock);
> +}
> +
>   /**
>    * __thermal_cooling_device_register() - register a new thermal cooling device
>    * @np:		a pointer to a device tree node.
> @@ -987,7 +1001,6 @@ __thermal_cooling_device_register(struct
>   				  const struct thermal_cooling_device_ops *ops)
>   {
>   	struct thermal_cooling_device *cdev;
> -	struct thermal_zone_device *pos;
>   	unsigned long current_state;
>   	int id, ret;
>   
> @@ -1054,16 +1067,7 @@ __thermal_cooling_device_register(struct
>   	if (current_state <= cdev->max_state)
>   		thermal_debug_cdev_add(cdev, current_state);
>   
> -	/* Add 'this' new cdev to the global cdev list */
> -	mutex_lock(&thermal_list_lock);
> -
> -	list_add(&cdev->node, &thermal_cdev_list);
> -
> -	/* Update binding information for 'this' new cdev */
> -	list_for_each_entry(pos, &thermal_tz_list, node)
> -		thermal_zone_cdev_bind(pos, cdev);
> -
> -	mutex_unlock(&thermal_list_lock);
> +	thermal_cooling_device_init_complete(cdev);
>   
>   	return cdev;
>   
> @@ -1274,38 +1278,42 @@ static void thermal_zone_cdev_unbind(str
>   	__thermal_zone_cdev_unbind(tz, cdev);
>   }
>   
> -/**
> - * thermal_cooling_device_unregister - removes a thermal cooling device
> - * @cdev:	the thermal cooling device to remove.
> - *
> - * thermal_cooling_device_unregister() must be called when a registered
> - * thermal cooling device is no longer needed.
> - */
> -void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
> +static bool thermal_cooling_device_exit(struct thermal_cooling_device *cdev)
>   {
>   	struct thermal_zone_device *tz;
> -
> -	if (!cdev)
> -		return;
> -
> -	thermal_debug_cdev_remove(cdev);
> +	bool ret = true;
>   
>   	mutex_lock(&thermal_list_lock);
>   
>   	if (!thermal_cooling_device_present(cdev)) {
> -		mutex_unlock(&thermal_list_lock);
> -		return;
> +		ret = false;
> +		goto unlock;
>   	}
>   
>   	list_del(&cdev->node);
>   
> -	/* Unbind all thermal zones associated with 'this' cdev */
>   	list_for_each_entry(tz, &thermal_tz_list, node)
>   		thermal_zone_cdev_unbind(tz, cdev);
>   
> +unlock:
>   	mutex_unlock(&thermal_list_lock);
>   
> -	device_unregister(&cdev->device);
> +	return ret;
> +}
> +
> +/**
> + * thermal_cooling_device_unregister() - removes a thermal cooling device
> + * @cdev: Thermal cooling device to remove.
> + */
> +void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
> +{
> +	if (!cdev)
> +		return;
> +
> +	thermal_debug_cdev_remove(cdev);
> +
> +	if (thermal_cooling_device_exit(cdev))
> +		device_unregister(&cdev->device);
>   }
>   EXPORT_SYMBOL_GPL(thermal_cooling_device_unregister);
>   
> 
> 
> 

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