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

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a0bd3208c0d88fd79c35397db5be8a71..106c69359306b595e74075853ae8cc4e1465924f 100644 (file)
--- 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);