1 files changed, 31 insertions, 8 deletions

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a0bd..106c69359306 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -108,6 +108,14 @@ static LIST_HEAD(dev_opp_list);
 /* Lock to allow exclusive modification to the device and opp lists */
 static DEFINE_MUTEX(dev_opp_list_lock);
 
+#define opp_rcu_lockdep_assert()					\
+do {									\
+	rcu_lockdep_assert(rcu_read_lock_held() ||			\
+				lockdep_is_held(&dev_opp_list_lock),	\
+			   "Missing rcu_read_lock() or "		\
+			   "dev_opp_list_lock protection");		\
+} while (0)
+
 /**
  * find_device_opp() - find device_opp struct using device pointer
  * @dev:	device pointer used to lookup device OPPs
@@ -208,9 +216,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
  * This function returns the number of available opps if there are any,
  * else returns 0 if none or the corresponding error value.
  *
- * Locking: This function must be called under rcu_read_lock(). This function
- * internally references two RCU protected structures: device_opp and opp which
- * are safe as long as we are under a common RCU locked section.
+ * Locking: This function takes rcu_read_lock().
  */
 int dev_pm_opp_get_opp_count(struct device *dev)
 {
@@ -218,11 +224,14 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 	struct dev_pm_opp *temp_opp;
 	int count = 0;
 
+	rcu_read_lock();
+
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
-		int r = PTR_ERR(dev_opp);
-		dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
-		return r;
+		count = PTR_ERR(dev_opp);
+		dev_err(dev, "%s: device OPP not found (%d)\n",
+			__func__, count);
+		goto out_unlock;
 	}
 
 	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
@@ -230,6 +239,8 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 			count++;
 	}
 
+out_unlock:
+	rcu_read_unlock();
 	return count;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
@@ -267,6 +278,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
+	opp_rcu_lockdep_assert();
+
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
 		int r = PTR_ERR(dev_opp);
@@ -313,6 +326,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
+	opp_rcu_lockdep_assert();
+
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
 		return ERR_PTR(-EINVAL);
@@ -361,6 +376,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 	struct device_opp *dev_opp;
 	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
+	opp_rcu_lockdep_assert();
+
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
 		return ERR_PTR(-EINVAL);
@@ -783,9 +800,15 @@ void of_free_opp_table(struct device *dev)
 
 	/* Check for existing list for 'dev' */
 	dev_opp = find_device_opp(dev);
-	if (WARN(IS_ERR(dev_opp), "%s: dev_opp: %ld\n", dev_name(dev),
-		 PTR_ERR(dev_opp)))
+	if (IS_ERR(dev_opp)) {
+		int error = PTR_ERR(dev_opp);
+		if (error != -ENODEV)
+			WARN(1, "%s: dev_opp: %d\n",
+			     IS_ERR_OR_NULL(dev) ?
+					"Invalid device" : dev_name(dev),
+			     error);
 		return;
+	}
 
 	/* Hold our list modification lock here */
 	mutex_lock(&dev_opp_list_lock);