rt2x00: fix stop queue

Since we clear QUEUE_STARTED in rt2x00queue_stop_queue(), following
call to rt2x00queue_pause_queue() reduce to noop, i.e we do not
stop queue in mac80211.

To fix that introduce rt2x00queue_pause_queue_nocheck() function,
which will stop queue in mac80211 directly.

Note that rt2x00_start_queue() explicitly set QUEUE_PAUSED bit.

Note also that reordering operations i.e. first call to
rt2x00queue_pause_queue() and then clear QUEUE_STARTED bit, will race
with rt2x00queue_unpause_queue(), so calling ieee80211_stop_queue()
directly is the only available solution to fix the problem without
major rework.

Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00queue.c

@@ -936,13 +936,8 @@ void rt2x00queue_index_inc(struct queue_entry *entry, enum queue_index index)
 	spin_unlock_irqrestore(&queue->index_lock, irqflags);
 }
 
-void rt2x00queue_pause_queue(struct data_queue *queue)
+void rt2x00queue_pause_queue_nocheck(struct data_queue *queue)
 {
-	if (!test_bit(DEVICE_STATE_PRESENT, &queue->rt2x00dev->flags) ||
-	    !test_bit(QUEUE_STARTED, &queue->flags) ||
-	    test_and_set_bit(QUEUE_PAUSED, &queue->flags))
-		return;
-
 	switch (queue->qid) {
 	case QID_AC_VO:
 	case QID_AC_VI:
@@ -958,6 +953,15 @@ void rt2x00queue_pause_queue(struct data_queue *queue)
 		break;
 	}
 }
+void rt2x00queue_pause_queue(struct data_queue *queue)
+{
+	if (!test_bit(DEVICE_STATE_PRESENT, &queue->rt2x00dev->flags) ||
+	    !test_bit(QUEUE_STARTED, &queue->flags) ||
+	    test_and_set_bit(QUEUE_PAUSED, &queue->flags))
+		return;
+
+	rt2x00queue_pause_queue_nocheck(queue);
+}
 EXPORT_SYMBOL_GPL(rt2x00queue_pause_queue);
 
 void rt2x00queue_unpause_queue(struct data_queue *queue)
@@ -1019,7 +1023,7 @@ void rt2x00queue_stop_queue(struct data_queue *queue)
 		return;
 	}
 
-	rt2x00queue_pause_queue(queue);
+	rt2x00queue_pause_queue_nocheck(queue);
 
 	queue->rt2x00dev->ops->lib->stop_queue(queue);