diff --git a/net/tipc/link.c b/net/tipc/link.c
index a5ea19e..c1aba69 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -645,7 +645,7 @@
 {
 	struct tipc_msg *msg = buf_msg(skb_peek(list));
 	unsigned int maxwin = link->window;
-	unsigned int imp = msg_importance(msg);
+	unsigned int i, imp = msg_importance(msg);
 	uint mtu = link->mtu;
 	u16 ack = mod(link->rcv_nxt - 1);
 	u16 seqno = link->snd_nxt;
@@ -655,10 +655,11 @@
 	struct sk_buff_head *backlogq = &link->backlogq;
 	struct sk_buff *skb, *tmp;
 
-	/* Match backlog limit against msg importance: */
-	if (unlikely(link->backlog[imp].len >= link->backlog[imp].limit))
-		return link_schedule_user(link, list);
-
+	/* Match msg importance against this and all higher backlog limits: */
+	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
+		if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
+			return link_schedule_user(link, list);
+	}
 	if (unlikely(msg_size(msg) > mtu)) {
 		__skb_queue_purge(list);
 		return -EMSGSIZE;
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index c3e96e8..ff7362d 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -365,6 +365,9 @@
 		return false;
 	if (unlikely(max < (start + msz)))
 		return false;
+	if ((msg_importance(msg) < TIPC_SYSTEM_IMPORTANCE) &&
+	    (msg_importance(bmsg) == TIPC_SYSTEM_IMPORTANCE))
+		return false;
 
 	skb_put(bskb, pad + msz);
 	skb_copy_to_linear_data_offset(bskb, start, skb->data, msz);
@@ -448,6 +451,10 @@
 	bmsg = buf_msg(bskb);
 	tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 		      INT_H_SIZE, dnode);
+	if (msg_isdata(msg))
+		msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
+	else
+		msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
 	msg_set_seqno(bmsg, msg_seqno(msg));
 	msg_set_ack(bmsg, msg_ack(msg));
 	msg_set_bcast_ack(bmsg, msg_bcast_ack(msg));
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index 6ca2366..6caf16c 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -352,18 +352,22 @@
  */
 static inline u32 msg_importance(struct tipc_msg *m)
 {
-	if (unlikely(msg_user(m) == MSG_FRAGMENTER))
+	int usr = msg_user(m);
+
+	if (likely((usr <= TIPC_CRITICAL_IMPORTANCE) && !msg_errcode(m)))
+		return usr;
+	if ((usr == MSG_FRAGMENTER) || (usr == MSG_BUNDLER))
 		return msg_bits(m, 5, 13, 0x7);
-	if (likely(msg_isdata(m) && !msg_errcode(m)))
-		return msg_user(m);
 	return TIPC_SYSTEM_IMPORTANCE;
 }
 
 static inline void msg_set_importance(struct tipc_msg *m, u32 i)
 {
-	if (unlikely(msg_user(m) == MSG_FRAGMENTER))
+	int usr = msg_user(m);
+
+	if (likely((usr == MSG_FRAGMENTER) || (usr == MSG_BUNDLER)))
 		msg_set_bits(m, 5, 13, 0x7, i);
-	else if (likely(i < TIPC_SYSTEM_IMPORTANCE))
+	else if (i < TIPC_SYSTEM_IMPORTANCE)
 		msg_set_user(m, i);
 	else
 		pr_warn("Trying to set illegal importance in message\n");