iwlwifi: don't disable AGG queues that are not enabled

If the BA session is torn down before we had a chance to start it
we shouldn't disable the AGG tx queues that weren't enabled.
This can happen in two cases:

1) We get a delBA before we drained our Tx queues in agg start flow
2) We didn't get the (successfull) addBA response on time

Reported-by: Daniel Chyan <dchyan@princeton.edu>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-tx.c

@@ -590,11 +590,17 @@ int iwlagn_tx_agg_stop(struct iwl_priv *priv, struct ieee80211_vif *vif,
 	spin_unlock_bh(&priv->sta_lock);
 
 	if (test_bit(txq_id, priv->agg_q_alloc)) {
-		/* If the transport didn't know that we wanted to start
-		 * agreggation, don't tell it that we want to stop them
+		/*
+		 * If the transport didn't know that we wanted to start
+		 * agreggation, don't tell it that we want to stop them.
+		 * This can happen when we don't get the addBA response on
+		 * time, or we hadn't time to drain the AC queues.
 		 */
-		if (agg_state != IWL_AGG_STARTING)
+		if (agg_state == IWL_AGG_ON)
 			iwl_trans_tx_agg_disable(priv->trans, txq_id);
+		else
+			IWL_DEBUG_TX_QUEUES(priv, "Don't disable tx agg: %d\n",
+					    agg_state);
 		iwlagn_dealloc_agg_txq(priv, txq_id);
 	}