[PATCH v3 1/4] thermal: core: Add helpers to browse the cdev, tz and governor list

[Daniel Lezcano]

The cdev, tz and governor list, as well as their respective locks are
statically defined in the thermal_core.c file.

In order to give a sane access to these list, like browsing all the
thermal zones or all the cooling devices, let's define a set of
helpers where we pass a callback as a parameter to be called for each
thermal entity.

We keep the self-encapsulation and ensure the locks are correctly
taken when looking at the list.

Acked-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
 drivers/thermal/thermal_core.c | 51 ++++++++++++++++++++++++++++++++++
 drivers/thermal/thermal_core.h |  9 ++++++
 2 files changed, 60 insertions(+)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index b71196eaf90e..9caaa0b6d662 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -617,6 +617,57 @@ void thermal_zone_device_rebind_exception(struct thermal_zone_device *tz,
 	mutex_unlock(&thermal_list_lock);
 }
 
+int for_each_thermal_governor(int (*cb)(struct thermal_governor *, void *),
+			      void *data)
+{
+	struct thermal_governor *gov;
+	int ret = 0;
+
+	mutex_lock(&thermal_governor_lock);
+	list_for_each_entry(gov, &thermal_governor_list, governor_list) {
+		ret = cb(gov, data);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&thermal_governor_lock);
+
+	return ret;
+}
+
+int for_each_thermal_cooling_device(int (*cb)(struct thermal_cooling_device *,
+					      void *), void *data)
+{
+	struct thermal_cooling_device *cdev;
+	int ret = 0;
+
+	mutex_lock(&thermal_list_lock);
+	list_for_each_entry(cdev, &thermal_cdev_list, node) {
+		ret = cb(cdev, data);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&thermal_list_lock);
+
+	return ret;
+}
+
+int for_each_thermal_zone(int (*cb)(struct thermal_zone_device *, void *),
+			  void *data)
+{
+	struct thermal_zone_device *tz;
+	int ret = 0;
+
+	mutex_lock(&thermal_list_lock);
+	list_for_each_entry(tz, &thermal_tz_list, node) {
+		ret = cb(tz, data);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&thermal_list_lock);
+
+	return ret;
+}
+
 void thermal_zone_device_unbind_exception(struct thermal_zone_device *tz,
 					  const char *cdev_type, size_t size)
 {
diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index c95689586e19..71d88dac0791 100644
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -41,6 +41,15 @@ extern struct thermal_governor *__governor_thermal_table_end[];
 	     __governor < __governor_thermal_table_end;	\
 	     __governor++)
 
+int for_each_thermal_zone(int (*cb)(struct thermal_zone_device *, void *),
+			  void *);
+
+int for_each_thermal_cooling_device(int (*cb)(struct thermal_cooling_device *,
+					      void *), void *);
+
+int for_each_thermal_governor(int (*cb)(struct thermal_governor *, void *),
+			      void *thermal_governor);
+
 struct thermal_attr {
 	struct device_attribute attr;
 	char name[THERMAL_NAME_LENGTH];
-- 
2.17.1