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thermal/core: Create a helper __thermal_cdev_update() without a lock

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There is a need to have a helper function which updates cooling device
state from the governors code. With this change governor can use
lock and unlock while calling helper function. This avoid unnecessary
second time lock/unlock which was in previous solution present in
governor implementation. This new helper function must be called
with mutex 'cdev->lock' hold.

The changed been discussed and part of code presented in thread:
https://lore.kernel.org/linux-pm/20210419084536.25000-1-lukasz.luba@arm.com/

Co-developed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lore.kernel.org/r/20210422114308.29684-2-lukasz.luba@arm.com
This commit is contained in:
Lukasz Luba 2021-04-22 12:43:06 +01:00 • committed by Daniel Lezcano
parent 26b2f03d2a
commit b70dbf40eb
2 changed files with 18 additions and 10 deletions
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1
drivers/thermal/thermal_core.h
View file

@ -66,6 +66,7 @@ static inline bool cdev_is_power_actor(struct thermal_cooling_device *cdev)
} }
void thermal_cdev_update(struct thermal_cooling_device *); void thermal_cdev_update(struct thermal_cooling_device *);
void __thermal_cdev_update(struct thermal_cooling_device *cdev);
/** /**
* struct thermal_trip - representation of a point in temperature domain * struct thermal_trip - representation of a point in temperature domain

27
drivers/thermal/thermal_helpers.c
View file

@ -192,18 +192,11 @@ static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
thermal_cooling_device_stats_update(cdev, target); thermal_cooling_device_stats_update(cdev, target);
} }
void thermal_cdev_update(struct thermal_cooling_device *cdev) void __thermal_cdev_update(struct thermal_cooling_device *cdev)
{ {
struct thermal_instance *instance; struct thermal_instance *instance;
unsigned long target = 0; unsigned long target = 0;
mutex_lock(&cdev->lock);
/* cooling device is updated*/
if (cdev->updated) {
mutex_unlock(&cdev->lock);
return;
}
/* Make sure cdev enters the deepest cooling state */ /* Make sure cdev enters the deepest cooling state */
list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) { list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
dev_dbg(&cdev->device, "zone%d->target=%lu\n", dev_dbg(&cdev->device, "zone%d->target=%lu\n",
@ -216,11 +209,25 @@ void thermal_cdev_update(struct thermal_cooling_device *cdev)
thermal_cdev_set_cur_state(cdev, target); thermal_cdev_set_cur_state(cdev, target);
cdev->updated = true;
mutex_unlock(&cdev->lock);
trace_cdev_update(cdev, target); trace_cdev_update(cdev, target);
dev_dbg(&cdev->device, "set to state %lu\n", target); dev_dbg(&cdev->device, "set to state %lu\n", target);
} }
/**
* thermal_cdev_update - update cooling device state if needed
* @cdev: pointer to struct thermal_cooling_device
*
* Update the cooling device state if there is a need.
*/
void thermal_cdev_update(struct thermal_cooling_device *cdev)
{
mutex_lock(&cdev->lock);
if (!cdev->updated) {
__thermal_cdev_update(cdev);
cdev->updated = true;
}
mutex_unlock(&cdev->lock);
}
EXPORT_SYMBOL(thermal_cdev_update); EXPORT_SYMBOL(thermal_cdev_update);
/** /**