mac80211: tear down all agg queues when restart/reconfig hw

When there is a need to restart/reconfig hw, tear down all the
aggregation queues and let the mac80211 and driver get in-sync to have
the opportunity to re-establish the aggregation queues again.

Need to wait until driver re-establish all the station information before tear
down the aggregation queues, driver(at least iwlwifi driver) will reject the
stop aggregation queue request if station is not ready. But also need to make
sure the aggregation queues are tear down before waking up the queues, so
mac80211 will not sending frames with aggregation bit set.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/util.c

@@ -1178,6 +1178,14 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 		}
 	}
 
+	rcu_read_lock();
+	if (hw->flags & IEEE80211_HW_AMPDU_AGGREGATION) {
+		list_for_each_entry_rcu(sta, &local->sta_list, list) {
+			ieee80211_sta_tear_down_BA_sessions(sta);
+		}
+	}
+	rcu_read_unlock();
+
 	/* add back keys */
 	list_for_each_entry(sdata, &local->interfaces, list)
 		if (ieee80211_sdata_running(sdata))