Bluetooth: 6lowpan: Use netif APIs to flow control

Rely on netif_wake_queue and netif_stop_queue to flow control when
transmit resources are unavailable.
Signed-off-by: NLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
Acked-by: NJukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/bluetooth/6lowpan.c

@@ -867,12 +867,28 @@ static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 
 static void chan_suspend_cb(struct l2cap_chan *chan)
 {
+	struct lowpan_btle_dev *dev;
+
 	BT_DBG("chan %p suspend", chan);
+
+	dev = lookup_dev(chan->conn);
+	if (!dev || !dev->netdev)
+		return;
+
+	netif_stop_queue(dev->netdev);
 }
 
 static void chan_resume_cb(struct l2cap_chan *chan)
 {
+	struct lowpan_btle_dev *dev;
+
 	BT_DBG("chan %p resume", chan);
+
+	dev = lookup_dev(chan->conn);
+	if (!dev || !dev->netdev)
+		return;
+
+	netif_wake_queue(dev->netdev);
 }
 
 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)