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authorDoug Leith <doug.leith@nuim.ie>2008-11-12 01:41:09 -0800
committerDavid S. Miller <davem@davemloft.net>2008-11-12 01:41:09 -0800
commit8f65b5354b1a34a536641bd915958662e8af5320 (patch)
tree2870ccd815f0d8524487c1d33aa6349244e33b16 /net/ipv4/tcp_htcp.c
parentd809a1595610a7c0b0bd55f159e5dc37def0ac28 (diff)
downloadlwn-8f65b5354b1a34a536641bd915958662e8af5320.tar.gz
lwn-8f65b5354b1a34a536641bd915958662e8af5320.zip
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 <doug.leith@nuim.ie> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_htcp.c')
-rw-r--r--net/ipv4/tcp_htcp.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
index af99776146ff..937549b8a921 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: