From 0e1c54c2a405494281e0639aacc90db03b50ae77 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Sat, 20 Sep 2008 21:24:21 -0700 Subject: [PATCH] tcp: reorganize retransmit code loops MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: David S. Miller --- include/linux/tcp.h | 1 - include/net/tcp.h | 1 - net/ipv4/tcp_output.c | 79 ++++++++++++++++++------------------------- 3 files changed, 33 insertions(+), 48 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index d7637c4b284..76729062829 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -342,7 +342,6 @@ struct tcp_sock { struct sk_buff* lost_skb_hint; struct sk_buff *scoreboard_skb_hint; struct sk_buff *retransmit_skb_hint; - struct sk_buff *forward_skb_hint; struct sk_buff_head out_of_order_queue; /* Out of order segments go here */ diff --git a/include/net/tcp.h b/include/net/tcp.h index d0e90c50722..220f54cf42e 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1042,7 +1042,6 @@ static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) tp->lost_skb_hint = NULL; tp->scoreboard_skb_hint = NULL; tp->retransmit_skb_hint = NULL; - tp->forward_skb_hint = NULL; } /* MD5 Signature */ diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 9f44be633ef..b5b4ddcdda4 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2032,7 +2032,9 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 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 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 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 @@ -2060,65 +2063,49 @@ void tcp_xmit_retransmit_queue(struct sock *sk) */ 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)) - continue; - - if (!(sacked & TCPCB_LOST)) - 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)) - inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, - 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); + if (fwd_rexmitting) { +begin_fwd: + if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp))) + break; + mib_idx = LINUX_MIB_TCPFORWARDRETRANS; - tcp_for_write_queue_from(skb, sk) { - if (skb == tcp_send_head(sk)) - break; - tp->forward_skb_hint = skb; + } 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; - if (!before(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp))) - break; + } else if (!(sacked & TCPCB_LOST)) { + if (hole == NULL && !(sacked & TCPCB_SACKED_RETRANS)) + hole = skb; + continue; - if (tcp_packets_in_flight(tp) >= tp->snd_cwnd) - break; + } else { + if (icsk->icsk_ca_state != TCP_CA_Loss) + mib_idx = LINUX_MIB_TCPFASTRETRANS; + else + mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS; + } - if (TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS) + if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS)) continue; - /* Ok, retransmit it. */ if (tcp_retransmit_skb(sk, skb)) { - tp->forward_skb_hint = NULL; - break; + tp->retransmit_skb_hint = NULL; + return; } + NET_INC_STATS_BH(sock_net(sk), mib_idx); 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); } } -- 2.41.1