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Thermal: Introduce locking for cdev.thermal_instances list. 

we need to go over all the thermal_instance list of a cooling device
to decide which cooling state to put the cooling device to.

But at this time, as a cooling device may be referenced in multiple
thermal zones, we need to lock the list first in case
another thermal zone is updating this cooling device.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Eduardo Valentin <eduardo.valentin@ti.com>
This commit is contained in:
Zhang Rui 2012-07-24 16:56:21 +08:00
parent 908b9fb792
commit f4a821ce6e
2 changed files with 9 additions and 0 deletions
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8
drivers/thermal/thermal_sys.c
View File

@ -799,6 +799,7 @@ int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
goto remove_symbol_link;
mutex_lock(&tz->lock);
mutex_lock(&cdev->lock);
list_for_each_entry(pos, &tz->thermal_instances, tz_node)
if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
result = -EEXIST;
@ -808,6 +809,7 @@ int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
list_add_tail(&dev->tz_node, &tz->thermal_instances);
list_add_tail(&dev->cdev_node, &cdev->thermal_instances);
}
mutex_unlock(&cdev->lock);
mutex_unlock(&tz->lock);
if (!result)
@ -840,14 +842,17 @@ int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
struct thermal_instance *pos, *next;
mutex_lock(&tz->lock);
mutex_lock(&cdev->lock);
list_for_each_entry_safe(pos, next, &tz->thermal_instances, tz_node) {
if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
list_del(&pos->tz_node);
list_del(&pos->cdev_node);
mutex_unlock(&cdev->lock);
mutex_unlock(&tz->lock);
goto unbind;
}
}
mutex_unlock(&cdev->lock);
mutex_unlock(&tz->lock);
return -ENODEV;
@ -913,6 +918,7 @@ thermal_cooling_device_register(char *type, void *devdata,
}
strcpy(cdev->type, type);
mutex_init(&cdev->lock);
INIT_LIST_HEAD(&cdev->thermal_instances);
cdev->ops = ops;
cdev->updated = true;
@ -1016,6 +1022,7 @@ static void thermal_cdev_do_update(struct thermal_cooling_device *cdev)
if (cdev->updated)
return;
mutex_lock(&cdev->lock);
/* Make sure cdev enters the deepest cooling state */
list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
if (instance->target == THERMAL_NO_TARGET)
@ -1023,6 +1030,7 @@ static void thermal_cdev_do_update(struct thermal_cooling_device *cdev)
if (instance->target > target)
target = instance->target;
}
mutex_unlock(&cdev->lock);
cdev->ops->set_cur_state(cdev, target);
cdev->updated = true;
}

1
include/linux/thermal.h
View File

@ -95,6 +95,7 @@ struct thermal_cooling_device {
void *devdata;
const struct thermal_cooling_device_ops *ops;
bool updated; /* true if the cooling device does not need update */
struct mutex lock; /* protect thermal_instances list */
struct list_head thermal_instances;
struct list_head node;
};