Commit 8f65b535 authored by Doug Leith's avatar Doug Leith Committed by David S. Miller
Browse files

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: default avatarDoug Leith <doug.leith@nuim.ie>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d809a159
......@@ -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:
......
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