thermal: core: Add and use thermal zone guard

Add and use a guard for thermal zone locking.

This allows quite a few error code paths to be simplified among
other things and brings in a noticeable code size reduction for
a good measure.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/1930069.tdWV9SEqCh@rjwysocki.net
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

drivers/thermal/thermal_core.c

@@ -202,16 +202,13 @@ int thermal_zone_device_set_policy(struct thermal_zone_device *tz,
 	int ret = -EINVAL;
 
 	mutex_lock(&thermal_governor_lock);
-	mutex_lock(&tz->lock);
+
+	guard(thermal_zone)(tz);
 
 	gov = __find_governor(strim(policy));
-	if (!gov)
-		goto exit;
+	if (gov)
+		ret = thermal_set_governor(tz, gov);
 
-	ret = thermal_set_governor(tz, gov);
-
-exit:
-	mutex_unlock(&tz->lock);
 	mutex_unlock(&thermal_governor_lock);
 
 	thermal_notify_tz_gov_change(tz, policy);
@@ -617,26 +614,18 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
 {
 	int ret;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	/* do nothing if mode isn't changing */
-	if (mode == tz->mode) {
-		mutex_unlock(&tz->lock);
-
+	if (mode == tz->mode)
 		return 0;
-	}
 
 	ret = __thermal_zone_device_set_mode(tz, mode);
-	if (ret) {
-		mutex_unlock(&tz->lock);
-
+	if (ret)
 		return ret;
-	}
 
 	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 
-	mutex_unlock(&tz->lock);
-
 	if (mode == THERMAL_DEVICE_ENABLED)
 		thermal_notify_tz_enable(tz);
 	else
@@ -665,10 +654,10 @@ static bool thermal_zone_is_present(struct thermal_zone_device *tz)
 void thermal_zone_device_update(struct thermal_zone_device *tz,
 				enum thermal_notify_event event)
 {
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
+
 	if (thermal_zone_is_present(tz))
 		__thermal_zone_device_update(tz, event);
-	mutex_unlock(&tz->lock);
 }
 EXPORT_SYMBOL_GPL(thermal_zone_device_update);
 
@@ -972,12 +961,10 @@ static bool __thermal_zone_cdev_bind(struct thermal_zone_device *tz,
 static void thermal_zone_cdev_bind(struct thermal_zone_device *tz,
 				   struct thermal_cooling_device *cdev)
 {
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	if (__thermal_zone_cdev_bind(tz, cdev))
 		__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
-
-	mutex_unlock(&tz->lock);
 }
 
 /**
@@ -1284,11 +1271,9 @@ static void __thermal_zone_cdev_unbind(struct thermal_zone_device *tz,
 static void thermal_zone_cdev_unbind(struct thermal_zone_device *tz,
 				     struct thermal_cooling_device *cdev)
 {
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	__thermal_zone_cdev_unbind(tz, cdev);
-
-	mutex_unlock(&tz->lock);
 }
 
 /**
@@ -1334,7 +1319,7 @@ int thermal_zone_get_crit_temp(struct thermal_zone_device *tz, int *temp)
 	if (tz->ops.get_crit_temp)
 		return tz->ops.get_crit_temp(tz, temp);
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	for_each_trip_desc(tz, td) {
 		const struct thermal_trip *trip = &td->trip;
@@ -1346,8 +1331,6 @@ int thermal_zone_get_crit_temp(struct thermal_zone_device *tz, int *temp)
 		}
 	}
 
-	mutex_unlock(&tz->lock);
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(thermal_zone_get_crit_temp);
@@ -1360,7 +1343,7 @@ static void thermal_zone_init_complete(struct thermal_zone_device *tz)
 
 	list_add_tail(&tz->node, &thermal_tz_list);
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	/* Bind cooling devices for this zone. */
 	list_for_each_entry(cdev, &thermal_cdev_list, node)
@@ -1377,8 +1360,6 @@ static void thermal_zone_init_complete(struct thermal_zone_device *tz)
 
 	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 
-	mutex_unlock(&tz->lock);
-
 	mutex_unlock(&thermal_list_lock);
 }
 
@@ -1615,7 +1596,7 @@ static bool thermal_zone_exit(struct thermal_zone_device *tz)
 		goto unlock;
 	}
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	tz->state |= TZ_STATE_FLAG_EXIT;
 	list_del_init(&tz->node);
@@ -1624,8 +1605,6 @@ static bool thermal_zone_exit(struct thermal_zone_device *tz)
 	list_for_each_entry(cdev, &thermal_cdev_list, node)
 		__thermal_zone_cdev_unbind(tz, cdev);
 
-	mutex_unlock(&tz->lock);
-
 unlock:
 	mutex_unlock(&thermal_list_lock);
 
@@ -1710,7 +1689,7 @@ static void thermal_zone_device_resume(struct work_struct *work)
 
 	tz = container_of(work, struct thermal_zone_device, poll_queue.work);
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	tz->state &= ~(TZ_STATE_FLAG_SUSPENDED | TZ_STATE_FLAG_RESUMING);
 
@@ -1720,13 +1699,11 @@ static void thermal_zone_device_resume(struct work_struct *work)
 	__thermal_zone_device_update(tz, THERMAL_TZ_RESUME);
 
 	complete(&tz->resume);
-
-	mutex_unlock(&tz->lock);
 }
 
 static void thermal_zone_pm_prepare(struct thermal_zone_device *tz)
 {
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	if (tz->state & TZ_STATE_FLAG_RESUMING) {
 		/*
@@ -1742,13 +1719,11 @@ static void thermal_zone_pm_prepare(struct thermal_zone_device *tz)
 	}
 
 	tz->state |= TZ_STATE_FLAG_SUSPENDED;
-
-	mutex_unlock(&tz->lock);
 }
 
 static void thermal_zone_pm_complete(struct thermal_zone_device *tz)
 {
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	cancel_delayed_work(&tz->poll_queue);
 
@@ -1762,8 +1737,6 @@ static void thermal_zone_pm_complete(struct thermal_zone_device *tz)
 	INIT_DELAYED_WORK(&tz->poll_queue, thermal_zone_device_resume);
 	/* Queue up the work without a delay. */
 	mod_delayed_work(system_freezable_power_efficient_wq, &tz->poll_queue, 0);
-
-	mutex_unlock(&tz->lock);
 }
 
 static int thermal_pm_notify(struct notifier_block *nb,

drivers/thermal/thermal_core.h

@@ -9,6 +9,7 @@
 #ifndef __THERMAL_CORE_H__
 #define __THERMAL_CORE_H__
 
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/thermal.h>
 
@@ -146,6 +147,9 @@ struct thermal_zone_device {
 	struct thermal_trip_desc trips[] __counted_by(num_trips);
 };
 
+DEFINE_GUARD(thermal_zone, struct thermal_zone_device *, mutex_lock(&_T->lock),
+	     mutex_unlock(&_T->lock))
+
 /* Initial thermal zone temperature. */
 #define THERMAL_TEMP_INIT	INT_MIN
 

drivers/thermal/thermal_debugfs.c

@@ -885,6 +885,19 @@ void thermal_debug_tz_add(struct thermal_zone_device *tz)
 	tz->debugfs = thermal_dbg;
 }
 
+static struct thermal_debugfs *thermal_debug_tz_clear(struct thermal_zone_device *tz)
+{
+	struct thermal_debugfs *thermal_dbg;
+
+	guard(thermal_zone)(tz);
+
+	thermal_dbg = tz->debugfs;
+	if (thermal_dbg)
+		tz->debugfs = NULL;
+
+	return thermal_dbg;
+}
+
 void thermal_debug_tz_remove(struct thermal_zone_device *tz)
 {
 	struct thermal_debugfs *thermal_dbg;
@@ -892,17 +905,9 @@ void thermal_debug_tz_remove(struct thermal_zone_device *tz)
 	struct tz_debugfs *tz_dbg;
 	int *trips_crossed;
 
-	mutex_lock(&tz->lock);
-
-	thermal_dbg = tz->debugfs;
-	if (!thermal_dbg) {
-		mutex_unlock(&tz->lock);
+	thermal_dbg = thermal_debug_tz_clear(tz);
+	if (!thermal_dbg)
 		return;
-	}
-
-	tz->debugfs = NULL;
-
-	mutex_unlock(&tz->lock);
 
 	tz_dbg = &thermal_dbg->tz_dbg;
 

drivers/thermal/thermal_helpers.c

@@ -60,13 +60,13 @@ bool thermal_trip_is_bound_to_cdev(struct thermal_zone_device *tz,
 {
 	bool ret;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
+
 	mutex_lock(&cdev->lock);
 
 	ret = thermal_instance_present(tz, cdev, trip);
 
 	mutex_unlock(&cdev->lock);
-	mutex_unlock(&tz->lock);
 
 	return ret;
 }
@@ -138,19 +138,14 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 	if (IS_ERR_OR_NULL(tz))
 		return -EINVAL;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
-	if (!tz->ops.get_temp) {
-		ret = -EINVAL;
-		goto unlock;
-	}
+	if (!tz->ops.get_temp)
+		return -EINVAL;
 
 	ret = __thermal_zone_get_temp(tz, temp);
 	if (!ret && *temp <= THERMAL_TEMP_INVALID)
-		ret = -ENODATA;
-
-unlock:
-	mutex_unlock(&tz->lock);
+		return -ENODATA;
 
 	return ret;
 }

drivers/thermal/thermal_hwmon.c

@@ -78,12 +78,9 @@ temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
 	int temperature;
 	int ret;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	ret = tz->ops.get_crit_temp(tz, &temperature);
-
-	mutex_unlock(&tz->lock);
-
 	if (ret)
 		return ret;
 

drivers/thermal/thermal_netlink.c

@@ -459,7 +459,7 @@ static int thermal_genl_cmd_tz_get_trip(struct param *p)
 	if (!start_trip)
 		return -EMSGSIZE;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	for_each_trip_desc(tz, td) {
 		const struct thermal_trip *trip = &td->trip;
@@ -469,19 +469,12 @@ static int thermal_genl_cmd_tz_get_trip(struct param *p)
 		    nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_TRIP_TYPE, trip->type) ||
 		    nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_TRIP_TEMP, trip->temperature) ||
 		    nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_TRIP_HYST, trip->hysteresis))
-			goto out_cancel_nest;
+			return -EMSGSIZE;
 	}
 
-	mutex_unlock(&tz->lock);
-
 	nla_nest_end(msg, start_trip);
 
 	return 0;
-
-out_cancel_nest:
-	mutex_unlock(&tz->lock);
-
-	return -EMSGSIZE;
 }
 
 static int thermal_genl_cmd_tz_get_temp(struct param *p)
@@ -512,7 +505,7 @@ static int thermal_genl_cmd_tz_get_temp(struct param *p)
 static int thermal_genl_cmd_tz_get_gov(struct param *p)
 {
 	struct sk_buff *msg = p->msg;
-	int id, ret = 0;
+	int id;
 
 	if (!p->attrs[THERMAL_GENL_ATTR_TZ_ID])
 		return -EINVAL;
@@ -523,16 +516,14 @@ static int thermal_genl_cmd_tz_get_gov(struct param *p)
 	if (!tz)
 		return -EINVAL;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	if (nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_ID, id) ||
 	    nla_put_string(msg, THERMAL_GENL_ATTR_TZ_GOV_NAME,
 			   tz->governor->name))
-		ret = -EMSGSIZE;
+		return -EMSGSIZE;
 
-	mutex_unlock(&tz->lock);
-
-	return ret;
+	return 0;
 }
 
 static int __thermal_genl_cmd_cdev_get(struct thermal_cooling_device *cdev,

drivers/thermal/thermal_sysfs.c

@@ -50,13 +50,13 @@ static ssize_t
 mode_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	int enabled;
 
-	mutex_lock(&tz->lock);
-	enabled = tz->mode == THERMAL_DEVICE_ENABLED;
-	mutex_unlock(&tz->lock);
+	guard(thermal_zone)(tz);
 
-	return sprintf(buf, "%s\n", enabled ? "enabled" : "disabled");
+	if (tz->mode == THERMAL_DEVICE_ENABLED)
+		return sprintf(buf, "enabled\n");
+
+	return sprintf(buf, "disabled\n");
 }
 
 static ssize_t
@@ -103,38 +103,34 @@ trip_point_temp_store(struct device *dev, struct device_attribute *attr,
 {
 	struct thermal_trip *trip = thermal_trip_of_attr(attr, temp);
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	int ret, temp;
+	int temp;
 
-	ret = kstrtoint(buf, 10, &temp);
-	if (ret)
+	if (kstrtoint(buf, 10, &temp))
 		return -EINVAL;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	if (temp == trip->temperature)
-		goto unlock;
+		return count;
 
 	/* Arrange the condition to avoid integer overflows. */
 	if (temp != THERMAL_TEMP_INVALID &&
-	    temp <= trip->hysteresis + THERMAL_TEMP_INVALID) {
-		ret = -EINVAL;
-		goto unlock;
-	}
+	    temp <= trip->hysteresis + THERMAL_TEMP_INVALID)
+		return -EINVAL;
 
 	if (tz->ops.set_trip_temp) {
+		int ret;
+
 		ret = tz->ops.set_trip_temp(tz, trip, temp);
 		if (ret)
-			goto unlock;
+			return ret;
 	}
 
 	thermal_zone_set_trip_temp(tz, trip, temp);
 
 	__thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
 
-unlock:
-	mutex_unlock(&tz->lock);
-
-	return ret ? ret : count;
+	return count;
 }
 
 static ssize_t
@@ -152,16 +148,15 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
 {
 	struct thermal_trip *trip = thermal_trip_of_attr(attr, hyst);
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	int ret, hyst;
+	int hyst;
 
-	ret = kstrtoint(buf, 10, &hyst);
-	if (ret || hyst < 0)
+	if (kstrtoint(buf, 10, &hyst) || hyst < 0)
 		return -EINVAL;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	if (hyst == trip->hysteresis)
-		goto unlock;
+		return count;
 
 	/*
 	 * Allow the hysteresis to be updated when the temperature is invalid
@@ -171,22 +166,17 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
 	 */
 	if (trip->temperature == THERMAL_TEMP_INVALID) {
 		WRITE_ONCE(trip->hysteresis, hyst);
-		goto unlock;
+		return count;
 	}
 
-	if (trip->temperature - hyst <= THERMAL_TEMP_INVALID) {
-		ret = -EINVAL;
-		goto unlock;
-	}
+	if (trip->temperature - hyst <= THERMAL_TEMP_INVALID)
+		return -EINVAL;
 
 	thermal_zone_set_trip_hyst(tz, trip, hyst);
 
 	__thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
 
-unlock:
-	mutex_unlock(&tz->lock);
-
-	return ret ? ret : count;
+	return count;
 }
 
 static ssize_t
@@ -236,25 +226,26 @@ emul_temp_store(struct device *dev, struct device_attribute *attr,
 		const char *buf, size_t count)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	int ret = 0;
 	int temperature;
 
 	if (kstrtoint(buf, 10, &temperature))
 		return -EINVAL;
 
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
+
+	if (tz->ops.set_emul_temp) {
+		int ret;
 
-	if (!tz->ops.set_emul_temp)
-		tz->emul_temperature = temperature;
-	else
 		ret = tz->ops.set_emul_temp(tz, temperature);
+		if (ret)
+			return ret;
+	} else {
+		tz->emul_temperature = temperature;
+	}
 
-	if (!ret)
-		__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
+	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 
-	mutex_unlock(&tz->lock);
-
-	return ret ? ret : count;
+	return count;
 }
 static DEVICE_ATTR_WO(emul_temp);
 #endif
@@ -894,13 +885,11 @@ ssize_t weight_store(struct device *dev, struct device_attribute *attr,
 	instance = container_of(attr, struct thermal_instance, weight_attr);
 
 	/* Don't race with governors using the 'weight' value */
-	mutex_lock(&tz->lock);
+	guard(thermal_zone)(tz);
 
 	instance->weight = weight;
 
 	thermal_governor_update_tz(tz, THERMAL_INSTANCE_WEIGHT_CHANGED);
 
-	mutex_unlock(&tz->lock);
-
 	return count;
 }

drivers/thermal/thermal_trip.c

@@ -45,13 +45,9 @@ int thermal_zone_for_each_trip(struct thermal_zone_device *tz,
 			       int (*cb)(struct thermal_trip *, void *),
 			       void *data)
 {
-	int ret;
+	guard(thermal_zone)(tz);
 
-	mutex_lock(&tz->lock);
-	ret = for_each_thermal_trip(tz, cb, data);
-	mutex_unlock(&tz->lock);
-
-	return ret;
+	return for_each_thermal_trip(tz, cb, data);
 }
 EXPORT_SYMBOL_GPL(thermal_zone_for_each_trip);