linux-kernel - Re: [PATCH v2 09/12] thermal: core: Update thermal zones after cooling device binding

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Message-ID: <be9ce314-57f1-4964-a1f5-0d8f466cc155@arm.com>
Date: Mon, 21 Oct 2024 23:35:42 +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 09/12] thermal: core: Update thermal zones after
 cooling device binding



On 10/4/24 20:33, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> If a new cooling device is registered and it is bound to at least one
> trip point in a given thermal zone, that thermal zone needs to be
> updated via __thermal_zone_device_update().
> 
> Instead of doing this with the help of the need_update atomic field in
> struct thermal_zone_device, which is not particularly straightforward,
> make __thermal_zone_cdev_bind() return a bool value indicating whether
> or not the given thermal zone needs to be updated because a new cooling
> device has been bound to it and update thermal_zone_cdev_bind() to
> call __thermal_zone_device_update() when this value is "true".
> 
> No intentional functional impact.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> 
> This is a new iteration of
> 
> https://lore.kernel.org/linux-pm/3603909.iIbC2pHGDl@rjwysocki.net/
> 
> v1 -> v2: Rebase.
> 
> ---
>   drivers/thermal/thermal_core.c |   23 +++++++++++++----------
>   1 file changed, 13 insertions(+), 10 deletions(-)
> 
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -933,13 +933,14 @@ void print_bind_err_msg(struct thermal_z
>   		cdev->type, thermal_zone_trip_id(tz, trip), ret);
>   }
>   
> -static void __thermal_zone_cdev_bind(struct thermal_zone_device *tz,
> +static bool __thermal_zone_cdev_bind(struct thermal_zone_device *tz,
>   				     struct thermal_cooling_device *cdev)
>   {
>   	struct thermal_trip_desc *td;
> +	bool update_tz = false;
>   
>   	if (!tz->ops.should_bind)
> -		return;
> +		return false;
>   
>   	for_each_trip_desc(tz, td) {
>   		struct thermal_trip *trip = &td->trip;
> @@ -954,9 +955,15 @@ static void __thermal_zone_cdev_bind(str
>   			continue;
>   
>   		ret = thermal_bind_cdev_to_trip(tz, trip, cdev, &c);
> -		if (ret)
> +		if (ret) {
>   			print_bind_err_msg(tz, trip, cdev, ret);
> +			continue;
> +		}
> +
> +		update_tz = true;
>   	}
> +
> +	return update_tz;
>   }
>   
>   static void thermal_zone_cdev_bind(struct thermal_zone_device *tz,
> @@ -964,7 +971,8 @@ static void thermal_zone_cdev_bind(struc
>   {
>   	mutex_lock(&tz->lock);
>   
> -	__thermal_zone_cdev_bind(tz, cdev);
> +	if (__thermal_zone_cdev_bind(tz, cdev))
> +		__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
>   
>   	mutex_unlock(&tz->lock);
>   }
> @@ -991,7 +999,7 @@ __thermal_cooling_device_register(struct
>   				  const struct thermal_cooling_device_ops *ops)
>   {
>   	struct thermal_cooling_device *cdev;
> -	struct thermal_zone_device *pos = NULL;
> +	struct thermal_zone_device *pos;
>   	unsigned long current_state;
>   	int id, ret;
>   
> @@ -1067,11 +1075,6 @@ __thermal_cooling_device_register(struct
>   	list_for_each_entry(pos, &thermal_tz_list, node)
>   		thermal_zone_cdev_bind(pos, cdev);
>   
> -	list_for_each_entry(pos, &thermal_tz_list, node)
> -		if (atomic_cmpxchg(&pos->need_update, 1, 0))
> -			thermal_zone_device_update(pos,
> -						   THERMAL_EVENT_UNSPECIFIED);
> -
>   	mutex_unlock(&thermal_list_lock);
>   
>   	return cdev;
> 
> 
> 

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