mac80211: clean up aggregation destruction

Yogesh's patch to destroy aggregation sessions when
stations are destroyed was needed, but unnecessarily
complex. Clean up this code.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/sta_info.c

@@ -815,34 +815,19 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
 	}
 #endif
 
-	/* There could be some memory leaks because of ampdu tx pending queue
-	 * not being freed before destroying the station info.
-	 *
-	 * Make sure that such queues are purged before freeing the station
-	 * info.
-	 * TODO: We have to somehow postpone the full destruction
-	 * until the aggregation stop completes. Refer
-	 * http://thread.gmane.org/gmane.linux.kernel.wireless.general/81936
+	/*
+	 * Destroy aggregation state here. It would be nice to wait for the
+	 * driver to finish aggregation stop and then clean up, but for now
+	 * drivers have to handle aggregation stop being requested, followed
+	 * directly by station destruction.
 	 */
-
-	mutex_lock(&sta->ampdu_mlme.mtx);
-
 	for (i = 0; i < STA_TID_NUM; i++) {
-		tid_tx = rcu_dereference_protected_tid_tx(sta, i);
+		tid_tx = rcu_dereference_raw(sta->ampdu_mlme.tid_tx[i]);
 		if (!tid_tx)
 			continue;
-		if (skb_queue_len(&tid_tx->pending)) {
-#ifdef CONFIG_MAC80211_HT_DEBUG
-			wiphy_debug(local->hw.wiphy, "TX A-MPDU  purging %d "
-				"packets for tid=%d\n",
-				skb_queue_len(&tid_tx->pending), i);
-#endif /* CONFIG_MAC80211_HT_DEBUG */
 		__skb_queue_purge(&tid_tx->pending);
+		kfree(tid_tx);
 	}
-		kfree_rcu(tid_tx, rcu_head);
-	}
-
-	mutex_unlock(&sta->ampdu_mlme.mtx);
 
 	sta_info_free(local, sta);