tcp: convert retransmit_cnt_hint to seqno
Main benefit in this is that we can then freely point
the retransmit_skb_hint to anywhere we want to because
there's no longer need to know what would be the count
changes involve, and since this is really used only as a
terminator, unnecessary work is one time walk at most,
and if some retransmissions are necessary after that
point later on, the walk is not full waste of time
anyway.
Since retransmit_high must be kept valid, all lost
markers must ensure that.
Now I also have learned how those "holes" in the
rexmittable skbs can appear, mtu probe does them. So
I removed the misleading comment as well.
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 1149095..cfae61b 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1838,7 +1838,7 @@
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
unsigned int mss = tcp_current_mss(sk, 0);
- int lost = 0;
+ u32 prior_lost = tp->lost_out;
tcp_for_write_queue(skb, sk) {
if (skb == tcp_send_head(sk))
@@ -1849,17 +1849,13 @@
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
tp->retrans_out -= tcp_skb_pcount(skb);
}
- if (!(TCP_SKB_CB(skb)->sacked & TCPCB_LOST)) {
- TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
- tp->lost_out += tcp_skb_pcount(skb);
- lost = 1;
- }
+ tcp_skb_mark_lost_uncond_verify(tp, skb);
}
}
tcp_clear_all_retrans_hints(tp);
- if (!lost)
+ if (prior_lost == tp->lost_out)
return;
if (tcp_is_reno(tp))
@@ -2009,15 +2005,11 @@
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
- int packet_cnt;
- if (tp->retransmit_skb_hint) {
+ if (tp->retransmit_skb_hint)
skb = tp->retransmit_skb_hint;
- packet_cnt = tp->retransmit_cnt_hint;
- } else {
+ else
skb = tcp_write_queue_head(sk);
- packet_cnt = 0;
- }
/* First pass: retransmit lost packets. */
if (tp->lost_out) {
@@ -2028,7 +2020,6 @@
break;
/* we could do better than to assign each time */
tp->retransmit_skb_hint = skb;
- tp->retransmit_cnt_hint = packet_cnt;
/* Assume this retransmit will generate
* only one packet for congestion window
@@ -2039,6 +2030,8 @@
*/
if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
return;
+ if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high))
+ break;
if (sacked & TCPCB_LOST) {
if (!(sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))) {
@@ -2059,10 +2052,6 @@
inet_csk(sk)->icsk_rto,
TCP_RTO_MAX);
}
-
- packet_cnt += tcp_skb_pcount(skb);
- if (packet_cnt >= tp->lost_out)
- break;
}
}
}