[PATCH 01/21] regulator: core: Reduce critical area in _regulator_get

@@ -1286,10 +1286,14 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 	if (dev && dev->of_node) {
 		node = of_get_regulator(dev, supply);
 		if (node) {
+			mutex_lock(&regulator_list_mutex);
 			list_for_each_entry(r, &regulator_list, list)
 				if (r->dev.parent &&
-					node == r->dev.of_node)
+				    node == r->dev.of_node) {
+					mutex_unlock(&regulator_list_mutex);
 					return r;
+				}
+			mutex_unlock(&regulator_list_mutex);
 			*ret = -EPROBE_DEFER;
 			return NULL;
 		} else {

@@ -1307,9 +1311,13 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 	if (dev)
 		devname = dev_name(dev);
 
+	mutex_lock(&regulator_list_mutex);
 	list_for_each_entry(r, &regulator_list, list)
-		if (strcmp(rdev_get_name(r), supply) == 0)
+		if (strcmp(rdev_get_name(r), supply) == 0) {
+			mutex_unlock(&regulator_list_mutex);
 			return r;
+		}
+	mutex_unlock(&regulator_list_mutex);
 
 	list_for_each_entry(map, &regulator_map_list, list) {
 		/* If the mapping has a device set up it must match */

@@ -1395,8 +1403,6 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
 	else
 		ret = -EPROBE_DEFER;
 
-	mutex_lock(&regulator_list_mutex);
-
 	rdev = regulator_dev_lookup(dev, id, &ret);
 	if (rdev)
 		goto found;

@@ -1408,7 +1414,7 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
 	 * succeed, so, quit with appropriate error value
 	 */
 	if (ret && ret != -ENODEV)
-		goto out;
+		return regulator;
 
 	if (!devname)
 		devname = "deviceless";

@@ -1428,34 +1434,26 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
 		dev_warn(dev, "dummy supplies not allowed\n");
 	}
 
-	mutex_unlock(&regulator_list_mutex);
 	return regulator;
 
 found:
-	if (rdev->exclusive) {
-		regulator = ERR_PTR(-EPERM);
-		goto out;
-	}
+	if (rdev->exclusive)
+		return ERR_PTR(-EPERM);
 
-	if (exclusive && rdev->open_count) {
-		regulator = ERR_PTR(-EBUSY);
-		goto out;
-	}
+	if (exclusive && rdev->open_count)
+		return ERR_PTR(-EBUSY);
 
 	ret = regulator_resolve_supply(rdev);
-	if (ret < 0) {
-		regulator = ERR_PTR(ret);
-		goto out;
-	}
+	if (ret < 0)
+		return ERR_PTR(ret);
 
 	if (!try_module_get(rdev->owner))
-		goto out;
+		return regulator;
 
 	regulator = create_regulator(rdev, dev, id);
 	if (regulator == NULL) {
-		regulator = ERR_PTR(-ENOMEM);
 		module_put(rdev->owner);
-		goto out;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	rdev->open_count++;

@@ -1469,9 +1467,6 @@ found:
 			rdev->use_count = 0;
 	}
 
-out:
-	mutex_unlock(&regulator_list_mutex);
-
 	return regulator;
 }