tcp: reorganize retransmit code loops
Both loops are quite similar, so they can be combined
with little effort. As a result, forward_skb_hint becomes
obsolete 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 9f44be6..b5b4ddc 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2032,7 +2032,9 @@
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
+ struct sk_buff *hole = NULL;
int mib_idx;
+ int fwd_rexmitting = 0;
if (!tp->lost_out)
tp->retransmit_high = tp->snd_una;
@@ -2049,7 +2051,8 @@
if (skb == tcp_send_head(sk))
break;
/* we could do better than to assign each time */
- tp->retransmit_skb_hint = skb;
+ if (hole == NULL)
+ tp->retransmit_skb_hint = skb;
/* Assume this retransmit will generate
* only one packet for congestion window
@@ -2060,22 +2063,43 @@
*/
if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
return;
- if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high))
- break;
- if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
+
+ if (fwd_rexmitting) {
+begin_fwd:
+ if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
+ break;
+ mib_idx = LINUX_MIB_TCPFORWARDRETRANS;
+
+ } else if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high)) {
+ if (!tcp_can_forward_retransmit(sk))
+ break;
+ /* Backtrack if necessary to non-L'ed skb */
+ if (hole != NULL) {
+ skb = hole;
+ hole = NULL;
+ }
+ fwd_rexmitting = 1;
+ goto begin_fwd;
+
+ } else if (!(sacked & TCPCB_LOST)) {
+ if (hole == NULL && !(sacked & TCPCB_SACKED_RETRANS))
+ hole = skb;
continue;
- if (!(sacked & TCPCB_LOST))
+ } else {
+ if (icsk->icsk_ca_state != TCP_CA_Loss)
+ mib_idx = LINUX_MIB_TCPFASTRETRANS;
+ else
+ mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS;
+ }
+
+ if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
continue;
if (tcp_retransmit_skb(sk, skb)) {
tp->retransmit_skb_hint = NULL;
return;
}
- if (icsk->icsk_ca_state != TCP_CA_Loss)
- mib_idx = LINUX_MIB_TCPFASTRETRANS;
- else
- mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS;
NET_INC_STATS_BH(sock_net(sk), mib_idx);
if (skb == tcp_write_queue_head(sk))
@@ -2083,43 +2107,6 @@
inet_csk(sk)->icsk_rto,
TCP_RTO_MAX);
}
-
- /* OK, demanded retransmission is finished. */
- if (!tcp_can_forward_retransmit(sk))
- return;
-
- if (tp->forward_skb_hint)
- skb = tp->forward_skb_hint;
- else
- skb = tcp_write_queue_head(sk);
-
- tcp_for_write_queue_from(skb, sk) {
- if (skb == tcp_send_head(sk))
- break;
- tp->forward_skb_hint = skb;
-
- if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
- break;
-
- if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
- break;
-
- if (TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS)
- continue;
-
- /* Ok, retransmit it. */
- if (tcp_retransmit_skb(sk, skb)) {
- tp->forward_skb_hint = NULL;
- break;
- }
-
- if (skb == tcp_write_queue_head(sk))
- inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
- inet_csk(sk)->icsk_rto,
- TCP_RTO_MAX);
-
- NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPFORWARDRETRANS);
- }
}
/* Send a fin. The caller locks the socket for us. This cannot be