From 8f65b5354b1a34a536641bd915958662e8af5320 Mon Sep 17 00:00:00 2001 From: Doug Leith Date: Wed, 12 Nov 2008 01:41:09 -0800 Subject: [PATCH] tcp_htcp: last_cong bug fix This patch fixes a minor bug in tcp_htcp.c which has been highlighted by Lachlan Andrew and Lawrence Stewart. Currently, the time since the last congestion event, which is stored in variable last_cong, is reset whenever there is a state change into TCP_CA_Open. This includes transitions of the type TCP_CA_Open->TCP_CA_Disorder->TCP_CA_Open which are not associated with backoff of cwnd. The patch changes last_cong to be updated only on transitions into TCP_CA_Open that occur after experiencing the congestion-related states TCP_CA_Loss, TCP_CA_Recovery, TCP_CA_CWR. Signed-off-by: Doug Leith Signed-off-by: David S. Miller --- net/ipv4/tcp_htcp.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c index af99776146f..937549b8a92 100644 --- a/net/ipv4/tcp_htcp.c +++ b/net/ipv4/tcp_htcp.c @@ -69,9 +69,12 @@ static u32 htcp_cwnd_undo(struct sock *sk) const struct tcp_sock *tp = tcp_sk(sk); struct htcp *ca = inet_csk_ca(sk); - ca->last_cong = ca->undo_last_cong; - ca->maxRTT = ca->undo_maxRTT; - ca->old_maxB = ca->undo_old_maxB; + if (ca->undo_last_cong) { + ca->last_cong = ca->undo_last_cong; + ca->maxRTT = ca->undo_maxRTT; + ca->old_maxB = ca->undo_old_maxB; + ca->undo_last_cong = 0; + } return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta); } @@ -268,7 +271,10 @@ static void htcp_state(struct sock *sk, u8 new_state) case TCP_CA_Open: { struct htcp *ca = inet_csk_ca(sk); - ca->last_cong = jiffies; + if (ca->undo_last_cong) { + ca->last_cong = jiffies; + ca->undo_last_cong = 0; + } } break; case TCP_CA_CWR: -- 2.41.1