[PATCH net-next v2 11/14] tipc: changes to general packet reception algorithm

[Jon Maloy <jon.maloy@ericsson.com>]

We change the order of checking for destination users when processing
incoming packets. By placing the checks for users that may potentially
replace the processed buffer, i.e., CHANGEOVER_PROTOCOL and
MSG_FRAGMENTER, in a separate step before we check for the true end
users, we get rid of a label and a 'goto', at the same time making the
code more comprehensible and easy to follow.

This commit does not change any functionality, it is just a cosmetic
code reshuffle.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
---
 net/tipc/link.c |   76 +++++++++++++++++++++++++++++--------------------------
 1 file changed, 40 insertions(+), 36 deletions(-)

diff --git a/net/tipc/link.c b/net/tipc/link.c
index b678c2e..663623c 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1484,7 +1484,7 @@ void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
 		if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
 			msg_user(msg) == LINK_PROTOCOL &&
 			(msg_type(msg) == RESET_MSG ||
-					msg_type(msg) == ACTIVATE_MSG) &&
+			 msg_type(msg) == ACTIVATE_MSG) &&
 			!msg_redundant_link(msg))
 			n_ptr->block_setup &= ~WAIT_PEER_DOWN;
 
@@ -1503,7 +1503,6 @@ void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
 		while ((crs != l_ptr->next_out) &&
 		       less_eq(buf_seqno(crs), ackd)) {
 			struct sk_buff *next = crs->next;
-
 			kfree_skb(crs);
 			crs = next;
 			released++;
@@ -1516,14 +1515,17 @@ void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
 		/* Try sending any messages link endpoint has pending */
 		if (unlikely(l_ptr->next_out))
 			tipc_link_push_queue(l_ptr);
+
 		if (unlikely(!list_empty(&l_ptr->waiting_ports)))
 			tipc_link_wakeup_ports(l_ptr, 0);
+
 		if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
 			l_ptr->stats.sent_acks++;
-			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
+			tipc_link_send_proto_msg(l_ptr, STATE_MSG,
+						 0, 0, 0, 0, 0);
 		}
 
-		/* Now (finally!) process the incoming message */
+		/* Process the incoming packet */
 		if (unlikely(!link_working_working(l_ptr))) {
 			if (msg_user(msg) == LINK_PROTOCOL) {
 				link_recv_proto_msg(l_ptr, buf);
@@ -1555,14 +1557,40 @@ void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
 		l_ptr->next_in_no++;
 		if (unlikely(l_ptr->oldest_deferred_in))
 			head = link_insert_deferred_queue(l_ptr, head);
-deliver:
-		if (likely(msg_isdata(msg))) {
+
+		/* Deliver packet/message to correct user: */
+		if (unlikely(msg_user(msg) ==  CHANGEOVER_PROTOCOL)) {
+			if (!tipc_link_tunnel_rcv(n_ptr, &buf)) {
+				tipc_node_unlock(n_ptr);
+				continue;
+			}
+			msg = buf_msg(buf);
+		} else if (msg_user(msg) == MSG_FRAGMENTER) {
+			int rc;
+
+			l_ptr->stats.recv_fragments++;
+			rc = tipc_link_frag_rcv(&l_ptr->reasm_head,
+						&l_ptr->reasm_tail,
+						&buf);
+			if (rc == LINK_REASM_COMPLETE) {
+				l_ptr->stats.recv_fragmented++;
+				msg = buf_msg(buf);
+			} else {
+				if (rc == LINK_REASM_ERROR)
+					tipc_link_reset(l_ptr);
+				tipc_node_unlock(n_ptr);
+				continue;
+			}
+		}
+
+		switch (msg_user(msg)) {
+		case TIPC_LOW_IMPORTANCE:
+		case TIPC_MEDIUM_IMPORTANCE:
+		case TIPC_HIGH_IMPORTANCE:
+		case TIPC_CRITICAL_IMPORTANCE:
 			tipc_node_unlock(n_ptr);
 			tipc_port_recv_msg(buf);
 			continue;
-		}
-		switch (msg_user(msg)) {
-			int ret;
 		case MSG_BUNDLER:
 			l_ptr->stats.recv_bundles++;
 			l_ptr->stats.recv_bundled += msg_msgcnt(msg);
@@ -1574,44 +1602,20 @@ deliver:
 			tipc_node_unlock(n_ptr);
 			tipc_named_recv(buf);
 			continue;
-		case BCAST_PROTOCOL:
-			tipc_link_recv_sync(n_ptr, buf);
-			tipc_node_unlock(n_ptr);
-			continue;
 		case CONN_MANAGER:
 			tipc_node_unlock(n_ptr);
 			tipc_port_recv_proto_msg(buf);
 			continue;
-		case MSG_FRAGMENTER:
-			l_ptr->stats.recv_fragments++;
-			ret = tipc_link_frag_rcv(&l_ptr->reasm_head,
-						 &l_ptr->reasm_tail,
-						 &buf);
-			if (ret == LINK_REASM_COMPLETE) {
-				l_ptr->stats.recv_fragmented++;
-				msg = buf_msg(buf);
-				goto deliver;
-			}
-			if (ret == LINK_REASM_ERROR)
-				tipc_link_reset(l_ptr);
-			tipc_node_unlock(n_ptr);
-			continue;
-		case CHANGEOVER_PROTOCOL:
-			if (!tipc_link_tunnel_rcv(n_ptr, &buf))
-				break;
-			msg = buf_msg(buf);
-			seq_no = msg_seqno(msg);
-			goto deliver;
+		case BCAST_PROTOCOL:
+			tipc_link_recv_sync(n_ptr, buf);
+			break;
 		default:
 			kfree_skb(buf);
-			buf = NULL;
 			break;
 		}
 		tipc_node_unlock(n_ptr);
-		tipc_net_route_msg(buf);
 		continue;
 unlock_discard:
-
 		tipc_node_unlock(n_ptr);
 discard:
 		kfree_skb(buf);
-- 
1.7.9.5