Commit 1b69d745 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP]: Restore 2.6.24 mark_head_lost behavior for newreno/fack 



The fast retransmission can be forced locally to the rfc3517
branch in tcp_update_scoreboard instead of making such fragile
constructs deeper in tcp_mark_head_lost.

This is necessary for the next patch which must not have
loopholes for cnt > packets check. As one can notice,
readability got some improvements too because of this :-).

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bfe87dbc

net/ipv4/tcp_input.c

+8 −8
Original line number Diff line number Diff line
@@ -2134,7 +2134,7 @@ static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb) 
/* Mark head of queue up as lost. With RFC3517 SACK, the packets is

 * is against sacked "cnt", otherwise it's against facked "cnt"

 */

static void tcp_mark_head_lost(struct sock *sk, int packets, int fast_rexmit)

static void tcp_mark_head_lost(struct sock *sk, int packets)

{

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *skb;
@@ -2161,7 +2161,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int fast_rexmit) 
		    (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))

			cnt += tcp_skb_pcount(skb);



		if (((!fast_rexmit || (tp->lost_out > 0)) && (cnt > packets)) ||

		if ((cnt > packets) ||

		    after(TCP_SKB_CB(skb)->end_seq, tp->high_seq))

			break;

		if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_SACKED_ACKED|TCPCB_LOST))) {
@@ -2180,17 +2180,17 @@ static void tcp_update_scoreboard(struct sock *sk, int fast_rexmit) 
	struct tcp_sock *tp = tcp_sk(sk);



	if (tcp_is_reno(tp)) {

		tcp_mark_head_lost(sk, 1, fast_rexmit);

		tcp_mark_head_lost(sk, 1);

	} else if (tcp_is_fack(tp)) {

		int lost = tp->fackets_out - tp->reordering;

		if (lost <= 0)

			lost = 1;

		tcp_mark_head_lost(sk, lost, fast_rexmit);

		tcp_mark_head_lost(sk, lost);

	} else {

		int sacked_upto = tp->sacked_out - tp->reordering;

		if (sacked_upto < 0)

			sacked_upto = 0;

		tcp_mark_head_lost(sk, sacked_upto, fast_rexmit);

		if (sacked_upto < fast_rexmit)

			sacked_upto = fast_rexmit;

		tcp_mark_head_lost(sk, sacked_upto);

	}



	/* New heuristics: it is possible only after we switched
@@ -2524,7 +2524,7 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag) 
	    before(tp->snd_una, tp->high_seq) &&

	    icsk->icsk_ca_state != TCP_CA_Open &&

	    tp->fackets_out > tp->reordering) {

		tcp_mark_head_lost(sk, tp->fackets_out - tp->reordering, 0);

		tcp_mark_head_lost(sk, tp->fackets_out - tp->reordering);

		NET_INC_STATS_BH(LINUX_MIB_TCPLOSS);

	}

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