mac80211: Assign next hop address to pending mesh frames

Assign next hop address to pending mesh frames once the path is resolved.

Regression.  Frames transmitted when a mesh path was wating to be resolved were
being transmitted with an invalid Receiver Address.

[Changes since v1]

Suggested by Johannes:
 - Improved frame_queue traversal
 - Narower RCU scope
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Andrey Yurovsky <andrey@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/mesh_pathtbl.c

@@ -55,7 +55,25 @@ static DEFINE_RWLOCK(pathtbl_resize_lock);
  */
 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 {
+	struct sk_buff *skb;
+	struct ieee80211_hdr *hdr;
+	struct sk_buff_head tmpq;
+	unsigned long flags;
+
 	rcu_assign_pointer(mpath->next_hop, sta);
+
+	__skb_queue_head_init(&tmpq);
+
+	spin_lock_irqsave(&mpath->frame_queue.lock, flags);
+
+	while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
+		hdr = (struct ieee80211_hdr *) skb->data;
+		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
+		__skb_queue_tail(&tmpq, skb);
+	}
+
+	skb_queue_splice(&tmpq, &mpath->frame_queue);
+	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 }