mac80211: Ensure off-channel frames don't get queued

Commit 6c17b77b67 (mac80211: Fix tx queue
handling during scans) contains a bug that causes off-channel frames to
get queued when they should be handed down to the driver for transmit.
Prevent this from happening.

Reported-by: Fabio Rossi <rossi.f@inwind.it>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -1231,34 +1231,40 @@ static bool ieee80211_tx_frags(struct ieee80211_local *local,
 		if (local->queue_stop_reasons[q] ||
 		    (!txpending && !skb_queue_empty(&local->pending[q]))) {
 			if (unlikely(info->flags &
-					IEEE80211_TX_INTFL_OFFCHAN_TX_OK &&
+				     IEEE80211_TX_INTFL_OFFCHAN_TX_OK)) {
-				     local->queue_stop_reasons[q] &
+				if (local->queue_stop_reasons[q] &
-					~BIT(IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL))) {
+				    ~BIT(IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL)) {
+					/*
+					 * Drop off-channel frames if queues
+					 * are stopped for any reason other
+					 * than off-channel operation. Never
+					 * queue them.
+					 */
+					spin_unlock_irqrestore(
+						&local->queue_stop_reason_lock,
+						flags);
+					ieee80211_purge_tx_queue(&local->hw,
+								 skbs);
+					return true;
+				}
+			} else {
+
 				/*
-				 * Drop off-channel frames if queues are stopped
+				 * Since queue is stopped, queue up frames for
-				 * for any reason other than off-channel
+				 * later transmission from the tx-pending
-				 * operation. Never queue them.
+				 * tasklet when the queue is woken again.
 				 */
-				spin_unlock_irqrestore(
+				if (txpending)
-					&local->queue_stop_reason_lock, flags);
+					skb_queue_splice_init(skbs,
-				ieee80211_purge_tx_queue(&local->hw, skbs);
+							      &local->pending[q]);
-				return true;
+				else
+					skb_queue_splice_tail_init(skbs,
+								   &local->pending[q]);
+
+				spin_unlock_irqrestore(&local->queue_stop_reason_lock,
+						       flags);
+				return false;
 			}
-
-			/*
-			 * Since queue is stopped, queue up frames for later
-			 * transmission from the tx-pending tasklet when the
-			 * queue is woken again.
-			 */
-			if (txpending)
-				skb_queue_splice_init(skbs, &local->pending[q]);
-			else
-				skb_queue_splice_tail_init(skbs,
-							   &local->pending[q]);
-
-			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
-					       flags);
-			return false;
 		}
 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);