[PATCH v1] thermal: core: Clean up thermal_list_lock locking

[PATCH v1] thermal: core: Clean up thermal_list_lock locking

[Rafael J. Wysocki]

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>
---
 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;

Re: [PATCH v1] thermal: core: Clean up thermal_list_lock locking

[Daniel Lezcano]

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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Re: [PATCH v1] thermal: core: Clean up thermal_list_lock locking

[Rafael J. Wysocki]

On Sat, Apr 1, 2023 at 10:45 PM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> 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 ?

No, I;ll take care of it myself, thanks!

> >   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;
> >
> >
> >
>
> --
> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>
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>