Re: [PATCH v2 05/11] thermal: core: Call thermal_governor_update_tz() outside of cdev lock

Lukasz Luba
2024-10-22T21:09:48Z

On 10/10/24 23:12, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Holding a cooling device lock under thermal_governor_update_tz() is not
> necessary and it may cause lockdep to complain if any governor's
> .update_tz() callback attempts to lock a cdev.
>
> For this reason, move the thermal_governor_update_tz() calls in
> thermal_bind_cdev_to_trip() and thermal_unbind_cdev_from_trip() from
> under the cdev lock.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> This is a resend of
>
> https://lore.kernel.org/linux-pm/1921484.CQOukoFCf9@rjwysocki.net/
>
> ---
> drivers/thermal/thermal_core.c | 11 +++++------
> 1 file changed, 5 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
> @@ -832,13 +832,13 @@ static int thermal_bind_cdev_to_trip(str
> if (!result) {
> list_add_tail(&dev->trip_node, &td->thermal_instances);
> list_add_tail(&dev->cdev_node, &cdev->thermal_instances);
> -
> - thermal_governor_update_tz(tz, THERMAL_TZ_BIND_CDEV);
> }
> mutex_unlock(&cdev->lock);
>
> - if (!result)
> + if (!result) {
> + thermal_governor_update_tz(tz, THERMAL_TZ_BIND_CDEV);
> return 0;
> + }
>
> device_remove_file(&tz->device, &dev->weight_attr);
> remove_trip_file:
> @@ -873,9 +873,6 @@ static void thermal_unbind_cdev_from_tri
> if (pos->cdev == cdev) {
> list_del(&pos->trip_node);
> list_del(&pos->cdev_node);
> -
> - thermal_governor_update_tz(tz, THERMAL_TZ_UNBIND_CDEV);
> -
> mutex_unlock(&cdev->lock);
> goto unbind;
> }
> @@ -885,6 +882,8 @@ static void thermal_unbind_cdev_from_tri
> return;
>
> unbind:
> + thermal_governor_update_tz(tz, THERMAL_TZ_UNBIND_CDEV);
> +
> device_remove_file(&tz->device, &pos->weight_attr);
> device_remove_file(&tz->device, &pos->attr);
> sysfs_remove_link(&tz->device.kobj, pos->name);
>
>
>

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