Merge branch 'pm-opp'

* pm-opp:
  PM / OPP: take RCU lock in dev_pm_opp_get_opp_count
  PM / OPP: fix warning in of_free_opp_table()
  PM / OPP: add some lockdep annotations

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);