[TCP] Westwood: fix first sample
Need to update send sequence number tracking after first ack.
Rework of patch from Luca De Cicco.
Signed-off-by: Stephen Hemminger <shemminger@dxpl.pdx.osdl.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
index 29eb258..62a96b7 100644
--- a/net/ipv4/tcp_westwood.c
+++ b/net/ipv4/tcp_westwood.c
@@ -22,6 +22,7 @@
u32 accounted;
u32 rtt;
u32 rtt_min; /* minimum observed RTT */
+ u8 first_ack; /* flag which infers that this is the first ack */
};
@@ -52,6 +53,7 @@
w->rtt_min = w->rtt = TCP_WESTWOOD_INIT_RTT;
w->rtt_win_sx = tcp_time_stamp;
w->snd_una = tcp_sk(sk)->snd_una;
+ w->first_ack = 1;
}
/*
@@ -91,6 +93,15 @@
struct westwood *w = inet_csk_ca(sk);
s32 delta = tcp_time_stamp - w->rtt_win_sx;
+ /* Initialise w->snd_una with the first acked sequence number in order
+ * to fix mismatch between tp->snd_una and w->snd_una for the first
+ * bandwidth sample
+ */
+ if (w->first_ack) {
+ w->snd_una = tcp_sk(sk)->snd_una;
+ w->first_ack = 0;
+ }
+
/*
* See if a RTT-window has passed.
* Be careful since if RTT is less than
@@ -180,7 +191,7 @@
{
struct tcp_sock *tp = tcp_sk(sk);
struct westwood *w = inet_csk_ca(sk);
-
+
switch(event) {
case CA_EVENT_FAST_ACK:
westwood_fast_bw(sk);