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Message-ID: <3dbb630f-abf9-4d09-f1fd-b2b05013c5dd@linaro.org>
Date:   Sat, 1 Apr 2023 22:44:58 +0200
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Subject: Re: [PATCH v1] thermal: core: Clean up thermal_list_lock locking
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To:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux PM <linux-pm@vger.kernel.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
References: <2696911.mvXUDI8C0e@kreacher>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <2696911.mvXUDI8C0e@kreacher>
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On 22/03/2023 20:34, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Once thermal_list_lock has been acquired in
> __thermal_cooling_device_register(), it is not necessary to drop it
> and take it again until all of the thermal zones have been updated,
> so change the code accordingly.
> 
> No expected functional impact.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---

Looks good to me, shall I pick it in my branch ?


>   drivers/thermal/thermal_core.c |    8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
> 
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -826,8 +826,6 @@ static void bind_cdev(struct thermal_coo
>   	const struct thermal_zone_params *tzp;
>   	struct thermal_zone_device *pos = NULL;
>   
> -	mutex_lock(&thermal_list_lock);
> -
>   	list_for_each_entry(pos, &thermal_tz_list, node) {
>   		if (!pos->tzp && !pos->ops->bind)
>   			continue;
> @@ -854,8 +852,6 @@ static void bind_cdev(struct thermal_coo
>   			       tzp->tbp[i].weight);
>   		}
>   	}
> -
> -	mutex_unlock(&thermal_list_lock);
>   }
>   
>   /**
> @@ -933,17 +929,17 @@ __thermal_cooling_device_register(struct
>   
>   	/* Add 'this' new cdev to the global cdev list */
>   	mutex_lock(&thermal_list_lock);
> +
>   	list_add(&cdev->node, &thermal_cdev_list);
> -	mutex_unlock(&thermal_list_lock);
>   
>   	/* Update binding information for 'this' new cdev */
>   	bind_cdev(cdev);
>   
> -	mutex_lock(&thermal_list_lock);
>   	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;
> 
> 
> 

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