tipc: add packet sequence number at instant of transmission

Currently, the packet sequence number is updated and added to each
packet at the moment a packet is added to the link backlog queue.
This is wasteful, since it forces the code to traverse the send
packet list packet by packet when adding them to the backlog queue.
It would be better to just splice the whole packet list into the
backlog queue when that is the right action to do.

In this commit, we do this change. Also, since the sequence numbers
cannot now be assigned to the packets at the moment they are added
the backlog queue, we do instead calculate and add them at the moment
of transmission, when the backlog queue has to be traversed anyway.
We do this in the function tipc_link_push_packet().

Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 9 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index c1aba69..fb2a003 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -653,7 +653,7 @@ int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 	struct tipc_media_addr *addr = &link->media_addr;
 	struct sk_buff_head *transmq = &link->transmq;
 	struct sk_buff_head *backlogq = &link->backlogq;
-	struct sk_buff *skb, *tmp;
+	struct sk_buff *skb, *bskb;
 
 	/* Match msg importance against this and all higher backlog limits: */
 	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
@@ -665,32 +665,36 @@ int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 		return -EMSGSIZE;
 	}
 	/* Prepare each packet for sending, and add to relevant queue: */
-	skb_queue_walk_safe(list, skb, tmp) {
-		__skb_unlink(skb, list);
+	while (skb_queue_len(list)) {
+		skb = skb_peek(list);
 		msg = buf_msg(skb);
 		msg_set_seqno(msg, seqno);
 		msg_set_ack(msg, ack);
 		msg_set_bcast_ack(msg, bc_last_in);
 
 		if (likely(skb_queue_len(transmq) < maxwin)) {
+			__skb_dequeue(list);
 			__skb_queue_tail(transmq, skb);
 			tipc_bearer_send(net, link->bearer_id, skb, addr);
 			link->rcv_unacked = 0;
 			seqno++;
 			continue;
 		}
-		if (tipc_msg_bundle(skb_peek_tail(backlogq), skb, mtu)) {
+		if (tipc_msg_bundle(skb_peek_tail(backlogq), msg, mtu)) {
+			kfree_skb(__skb_dequeue(list));
 			link->stats.sent_bundled++;
 			continue;
 		}
-		if (tipc_msg_make_bundle(&skb, mtu, link->addr)) {
+		if (tipc_msg_make_bundle(&bskb, msg, mtu, link->addr)) {
+			kfree_skb(__skb_dequeue(list));
+			__skb_queue_tail(backlogq, bskb);
+			link->backlog[msg_importance(buf_msg(bskb))].len++;
 			link->stats.sent_bundled++;
 			link->stats.sent_bundles++;
-			imp = msg_importance(buf_msg(skb));
+			continue;
 		}
-		__skb_queue_tail(backlogq, skb);
-		link->backlog[imp].len++;
-		seqno++;
+		link->backlog[imp].len += skb_queue_len(list);
+		skb_queue_splice_tail_init(list, backlogq);
 	}
 	link->snd_nxt = seqno;
 	return 0;
@@ -822,6 +826,7 @@ void tipc_link_push_packets(struct tipc_link *link)
 {
 	struct sk_buff *skb;
 	struct tipc_msg *msg;
+	u16 seqno = link->snd_nxt;
 	u16 ack = mod(link->rcv_nxt - 1);
 
 	while (skb_queue_len(&link->transmq) < link->window) {
@@ -831,12 +836,15 @@ void tipc_link_push_packets(struct tipc_link *link)
 		msg = buf_msg(skb);
 		link->backlog[msg_importance(msg)].len--;
 		msg_set_ack(msg, ack);
+		msg_set_seqno(msg, seqno);
+		seqno = mod(seqno + 1);
 		msg_set_bcast_ack(msg, link->owner->bclink.last_in);
 		link->rcv_unacked = 0;
 		__skb_queue_tail(&link->transmq, skb);
 		tipc_bearer_send(link->owner->net, link->bearer_id,
 				 skb, &link->media_addr);
 	}
+	link->snd_nxt = seqno;
 }
 
 void tipc_link_reset_all(struct tipc_node *node)
@@ -1526,6 +1534,11 @@ void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
 
 	tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, TUNNEL_PROTOCOL,
 		      FAILOVER_MSG, INT_H_SIZE, l_ptr->addr);
+
+	skb_queue_walk(&l_ptr->backlogq, skb) {
+		msg_set_seqno(buf_msg(skb), l_ptr->snd_nxt);
+		l_ptr->snd_nxt = mod(l_ptr->snd_nxt + 1);
+	}
 	skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
 	tipc_link_purge_backlog(l_ptr);
 	msgcount = skb_queue_len(&l_ptr->transmq);
@@ -1586,6 +1599,7 @@ void tipc_link_dup_queue_xmit(struct tipc_link *link,
 	struct tipc_msg tnl_hdr;
 	struct sk_buff_head *queue = &link->transmq;
 	int mcnt;
+	u16 seqno;
 
 	tipc_msg_init(link_own_addr(link), &tnl_hdr, TUNNEL_PROTOCOL,
 		      SYNCH_MSG, INT_H_SIZE, link->addr);
@@ -1617,6 +1631,11 @@ tunnel_queue:
 	}
 	if (queue == &link->backlogq)
 		return;
+	seqno = link->snd_nxt;
+	skb_queue_walk(&link->backlogq, skb) {
+		msg_set_seqno(buf_msg(skb), seqno);
+		seqno = mod(seqno + 1);
+	}
 	queue = &link->backlogq;
 	goto tunnel_queue;
 }