Merge branch 'pm-opp'

* pm-opp:
  PM / OPP: using kfree_rcu() to simplify the code
  PM / OPP: predictable fail results for opp_find* functions, v2
  PM / OPP: Export symbols for module usage.
  PM / OPP: RCU reclaim

drivers/base/power/opp.c

@@ -23,6 +23,7 @@
 #include <linux/rcupdate.h>
 #include <linux/opp.h>
 #include <linux/of.h>
+#include <linux/export.h>
 
 /*
  * Internal data structure organization with the OPP layer library is as
@@ -65,6 +66,7 @@ struct opp {
 	unsigned long u_volt;
 
 	struct device_opp *dev_opp;
+	struct rcu_head head;
 };
 
 /**
@@ -160,6 +162,7 @@ unsigned long opp_get_voltage(struct opp *opp)
 
 	return v;
 }
+EXPORT_SYMBOL(opp_get_voltage);
 
 /**
  * opp_get_freq() - Gets the frequency corresponding to an available opp
@@ -189,6 +192,7 @@ unsigned long opp_get_freq(struct opp *opp)
 
 	return f;
 }
+EXPORT_SYMBOL(opp_get_freq);
 
 /**
  * opp_get_opp_count() - Get number of opps available in the opp list
@@ -221,6 +225,7 @@ int opp_get_opp_count(struct device *dev)
 
 	return count;
 }
+EXPORT_SYMBOL(opp_get_opp_count);
 
 /**
  * opp_find_freq_exact() - search for an exact frequency
@@ -230,7 +235,10 @@ int opp_get_opp_count(struct device *dev)
  *
  * Searches for exact match in the opp list and returns pointer to the matching
  * opp if found, else returns ERR_PTR in case of error and should be handled
- * using IS_ERR.
+ * using IS_ERR. Error return values can be:
+ * EINVAL:	for bad pointer
+ * ERANGE:	no match found for search
+ * ENODEV:	if device not found in list of registered devices
  *
  * Note: available is a modifier for the search. if available=true, then the
  * match is for exact matching frequency and is available in the stored OPP
@@ -249,7 +257,7 @@ struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq,
 				bool available)
 {
 	struct device_opp *dev_opp;
-	struct opp *temp_opp, *opp = ERR_PTR(-ENODEV);
+	struct opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp)) {
@@ -268,6 +276,7 @@ struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq,
 
 	return opp;
 }
+EXPORT_SYMBOL(opp_find_freq_exact);
 
 /**
  * opp_find_freq_ceil() - Search for an rounded ceil freq
@@ -278,7 +287,11 @@ struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq,
  * for a device.
  *
  * Returns matching *opp and refreshes *freq accordingly, else returns
- * ERR_PTR in case of error and should be handled using IS_ERR.
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:	for bad pointer
+ * ERANGE:	no match found for search
+ * ENODEV:	if device not found in list of registered devices
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
  * protected pointer. The reason for the same is that the opp pointer which is
@@ -289,7 +302,7 @@ struct opp *opp_find_freq_exact(struct device *dev, unsigned long freq,
 struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq)
 {
 	struct device_opp *dev_opp;
-	struct opp *temp_opp, *opp = ERR_PTR(-ENODEV);
+	struct opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
@@ -298,7 +311,7 @@ struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq)
 
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp))
-		return opp;
+		return ERR_CAST(dev_opp);
 
 	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
 		if (temp_opp->available && temp_opp->rate >= *freq) {
@@ -310,6 +323,7 @@ struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq)
 
 	return opp;
 }
+EXPORT_SYMBOL(opp_find_freq_ceil);
 
 /**
  * opp_find_freq_floor() - Search for a rounded floor freq
@@ -320,7 +334,11 @@ struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq)
  * for a device.
  *
  * Returns matching *opp and refreshes *freq accordingly, else returns
- * ERR_PTR in case of error and should be handled using IS_ERR.
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:	for bad pointer
+ * ERANGE:	no match found for search
+ * ENODEV:	if device not found in list of registered devices
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
  * protected pointer. The reason for the same is that the opp pointer which is
@@ -331,7 +349,7 @@ struct opp *opp_find_freq_ceil(struct device *dev, unsigned long *freq)
 struct opp *opp_find_freq_floor(struct device *dev, unsigned long *freq)
 {
 	struct device_opp *dev_opp;
-	struct opp *temp_opp, *opp = ERR_PTR(-ENODEV);
+	struct opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
 	if (!dev || !freq) {
 		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
@@ -340,7 +358,7 @@ struct opp *opp_find_freq_floor(struct device *dev, unsigned long *freq)
 
 	dev_opp = find_device_opp(dev);
 	if (IS_ERR(dev_opp))
-		return opp;
+		return ERR_CAST(dev_opp);
 
 	list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
 		if (temp_opp->available) {
@@ -356,6 +374,7 @@ struct opp *opp_find_freq_floor(struct device *dev, unsigned long *freq)
 
 	return opp;
 }
+EXPORT_SYMBOL(opp_find_freq_floor);
 
 /**
  * opp_add()  - Add an OPP table from a table definitions
@@ -512,7 +531,7 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
 
 	list_replace_rcu(&opp->node, &new_opp->node);
 	mutex_unlock(&dev_opp_list_lock);
-	synchronize_rcu();
+	kfree_rcu(opp, head);
 
 	/* Notify the change of the OPP availability */
 	if (availability_req)
@@ -522,13 +541,10 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
 		srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_DISABLE,
 					 new_opp);
 
-	/* clean up old opp */
-	new_opp = opp;
-	goto out;
+	return 0;
 
 unlock:
 	mutex_unlock(&dev_opp_list_lock);
-out:
 	kfree(new_opp);
 	return r;
 }
@@ -552,6 +568,7 @@ int opp_enable(struct device *dev, unsigned long freq)
 {
 	return opp_set_availability(dev, freq, true);
 }
+EXPORT_SYMBOL(opp_enable);
 
 /**
  * opp_disable() - Disable a specific OPP
@@ -573,6 +590,7 @@ int opp_disable(struct device *dev, unsigned long freq)
 {
 	return opp_set_availability(dev, freq, false);
 }
+EXPORT_SYMBOL(opp_disable);
 
 #ifdef CONFIG_CPU_FREQ
 /**