Commit 9bff40fd authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

[TCP] FRTO: remove unnecessary fackets/sacked_out recounting 



F-RTO does not touch SACKED_ACKED bits at all, so there is no
need to recount them in tcp_enter_frto_loss. After removal of
the else branch, nested ifs can be combined.

This must also reset sacked_out when SACK is not in use as TCP
could have received some duplicate ACKs prior RTO. To achieve
that in a sane manner, tcp_reset_reno_sack was re-placed by the
previous patch.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4ddf6676

net/ipv4/tcp_input.c

+7 −16
Original line number Diff line number Diff line
@@ -1474,17 +1474,15 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag) 
{

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *skb;

	int cnt = 0;



	tp->sacked_out = 0;

	tp->lost_out = 0;

	tp->fackets_out = 0;

	tp->retrans_out = 0;

	if (IsReno(tp))

		tcp_reset_reno_sack(tp);



	tcp_for_write_queue(skb, sk) {

		if (skb == tcp_send_head(sk))

			break;

		cnt += tcp_skb_pcount(skb);

		/*

		 * Count the retransmission made on RTO correctly (only when

		 * waiting for the first ACK and did not get it)...
@@ -1498,20 +1496,13 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag) 
		} else {

			TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);

		}

		if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED)) {



			/* Do not mark those segments lost that were

			 * forward transmitted after RTO

			 */

			if (!after(TCP_SKB_CB(skb)->end_seq,

				   tp->frto_highmark)) {

		/* Don't lost mark skbs that were fwd transmitted after RTO */

		if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED) &&

		    !after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark)) {

			TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;

			tp->lost_out += tcp_skb_pcount(skb);

		}

		} else {

			tp->sacked_out += tcp_skb_pcount(skb);

			tp->fackets_out = cnt;

		}

	}

	tcp_sync_left_out(tp);

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