ieee802154: 6lowpan: change if lowpan dev is running

We don't need to check if the wpan interface is running because the
lowpan_rcv is the packet layer receive handler for the wpan interface.

Instead doing a check if wpan interface is running we should check if
the lowpan interface is running before starting 6lowpan adaptation layer.
Reviewed-by: NStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/ieee802154/6lowpan/rx.c

@@ -65,19 +65,20 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *wdev,
 		      struct packet_type *pt, struct net_device *orig_wdev)
 {
 	struct ieee802154_hdr hdr;
+	struct net_device *ldev;
 	int ret;
 
-	if (wdev->type != ARPHRD_IEEE802154 ||
-	    !wdev->ieee802154_ptr->lowpan_dev)
+	if (wdev->type != ARPHRD_IEEE802154)
+		goto drop;
+
+	ldev = wdev->ieee802154_ptr->lowpan_dev;
+	if (!ldev || !netif_running(ldev))
 		goto drop;
 
 	skb = skb_share_check(skb, GFP_ATOMIC);
 	if (!skb)
 		goto drop;
 
-	if (!netif_running(wdev))
-		goto drop_skb;
-
 	if (skb->pkt_type == PACKET_OTHERHOST)
 		goto drop_skb;