[TCP]: Access to highest_sack obsoletes forward_cnt_hint
In addition, added a reference about the purpose of the loop.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 666d8a5..b11025e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1945,33 +1945,28 @@
* and retransmission... Both ways have their merits...
*
* For now we do not retransmit anything, while we have some new
- * segments to send.
+ * segments to send. In the other cases, follow rule 3 for
+ * NextSeg() specified in RFC3517.
*/
if (tcp_may_send_now(sk))
return;
- if (tp->forward_skb_hint) {
+ /* If nothing is SACKed, highest_sack in the loop won't be valid */
+ if (!tp->sacked_out)
+ return;
+
+ if (tp->forward_skb_hint)
skb = tp->forward_skb_hint;
- packet_cnt = tp->forward_cnt_hint;
- } else{
+ else
skb = tcp_write_queue_head(sk);
- packet_cnt = 0;
- }
tcp_for_write_queue_from(skb, sk) {
if (skb == tcp_send_head(sk))
break;
- tp->forward_cnt_hint = packet_cnt;
tp->forward_skb_hint = skb;
- /* Similar to the retransmit loop above we
- * can pretend that the retransmitted SKB
- * we send out here will be composed of one
- * real MSS sized packet because tcp_retransmit_skb()
- * will fragment it if necessary.
- */
- if (++packet_cnt > tp->fackets_out)
+ if (after(TCP_SKB_CB(skb)->seq, tp->highest_sack))
break;
if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)