mac80211: expose API allowing station iteration

Allow drivers to iterate all stations currently uploaded to them.
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -4192,6 +4192,22 @@ void ieee80211_iterate_active_interfaces_rtnl(struct ieee80211_hw *hw,
 						struct ieee80211_vif *vif),
 					      void *data);
 
+/**
+ * ieee80211_iterate_stations_atomic - iterate stations
+ *
+ * This function iterates over all stations associated with a given
+ * hardware that are currently uploaded to the driver and calls the callback
+ * function for them.
+ * This function requires the iterator callback function to be atomic,
+ *
+ * @hw: the hardware struct of which the interfaces should be iterated over
+ * @iterator: the iterator function to call, cannot sleep
+ * @data: first argument of the iterator function
+ */
+void ieee80211_iterate_stations_atomic(struct ieee80211_hw *hw,
+				       void (*iterator)(void *data,
+						struct ieee80211_sta *sta),
+				       void *data);
 /**
  * ieee80211_queue_work - add work onto the mac80211 workqueue
  *

net/mac80211/util.c

@@ -693,6 +693,34 @@ void ieee80211_iterate_active_interfaces_rtnl(
 }
 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_rtnl);
 
+static void __iterate_stations(struct ieee80211_local *local,
+			       void (*iterator)(void *data,
+						struct ieee80211_sta *sta),
+			       void *data)
+{
+	struct sta_info *sta;
+
+	list_for_each_entry_rcu(sta, &local->sta_list, list) {
+		if (!sta->uploaded)
+			continue;
+
+		iterator(data, &sta->sta);
+	}
+}
+
+void ieee80211_iterate_stations_atomic(struct ieee80211_hw *hw,
+			void (*iterator)(void *data,
+					 struct ieee80211_sta *sta),
+			void *data)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+
+	rcu_read_lock();
+	__iterate_stations(local, iterator, data);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(ieee80211_iterate_stations_atomic);
+
 struct ieee80211_vif *wdev_to_ieee80211_vif(struct wireless_dev *wdev)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);