4 files changed, 37 insertions, 13 deletions

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 4609819..15eb744 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -237,14 +237,36 @@ void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
 	struct sk_buff *next;
 	unsigned int released = 0;
 
-	if (less_eq(acked, n_ptr->bclink.acked))
-		return;
-
 	spin_lock_bh(&bc_lock);
 
-	/* Skip over packets that node has previously acknowledged */
-
+	/* Bail out if tx queue is empty (no clean up is required) */
 	crs = bcl->first_out;
+	if (!crs)
+		goto exit;
+
+	/* Determine which messages need to be acknowledged */
+	if (acked == INVALID_LINK_SEQ) {
+		/*
+		 * Contact with specified node has been lost, so need to
+		 * acknowledge sent messages only (if other nodes still exist)
+		 * or both sent and unsent messages (otherwise)
+		 */
+		if (bclink->bcast_nodes.count)
+			acked = bcl->fsm_msg_cnt;
+		else
+			acked = bcl->next_out_no;
+	} else {
+		/*
+		 * Bail out if specified sequence number does not correspond
+		 * to a message that has been sent and not yet acknowledged
+		 */
+		if (less(acked, buf_seqno(crs)) ||
+		    less(bcl->fsm_msg_cnt, acked) ||
+		    less_eq(acked, n_ptr->bclink.acked))
+			goto exit;
+	}
+
+	/* Skip over packets that node has previously acknowledged */
 	while (crs && less_eq(buf_seqno(crs), n_ptr->bclink.acked))
 		crs = crs->next;
 
@@ -255,8 +277,6 @@ void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
 
 		if (crs != bcl->next_out)
 			bcbuf_decr_acks(crs);
-		else if (bclink->bcast_nodes.count)
-			break;
 		else {
 			bcbuf_set_acks(crs, 0);
 			bcl->next_out = next;
@@ -281,6 +301,7 @@ void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
 	}
 	if (unlikely(released && !list_empty(&bcl->waiting_ports)))
 		tipc_link_wakeup_ports(bcl, 0);
+exit:
 	spin_unlock_bh(&bc_lock);
 }
 
diff --git a/net/tipc/link.c b/net/tipc/link.c
index 332915e..4eff342 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1733,10 +1733,8 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
 
 		/* Release acked messages */
 
-		if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
-			if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
-				tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
-		}
+		if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
+			tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
 
 		crs = l_ptr->first_out;
 		while ((crs != l_ptr->next_out) &&
diff --git a/net/tipc/link.h b/net/tipc/link.h
index e56cb53..7879239 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -45,6 +45,12 @@
 #define PUSH_FINISHED 2
 
 /*
+ * Out-of-range value for link sequence numbers
+ */
+
+#define INVALID_LINK_SEQ 0x10000
+
+/*
  * Link states
  */
 
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 1861ae9..e530de2 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -351,8 +351,7 @@ static void node_lost_contact(struct tipc_node *n_ptr)
 		}
 
 		tipc_bclink_remove_node(n_ptr->addr);
-		tipc_bclink_acknowledge(n_ptr,
-					mod(n_ptr->bclink.acked + 10000));
+		tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
 		if (n_ptr->addr < tipc_own_addr)
 			tipc_own_tag--;