[TCP]: Never TSO defer under periods of congestion.

Congestion window recover after loss depends upon the fact
that if we have a full MSS sized frame at the head of the
send queue, we will send it.  TSO deferral can defeat the
ACK clocking necessary to exit cleanly from recovery.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index fd3ce38184ae599469e247f44c421473ca7422e9..e041d057ec8607150b6b5c9b4801664c338506aa 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -909,6 +909,9 @@ static int tcp_tso_should_defer(struct sock *sk, struct tcp_sock *tp, struct sk_
        if (TCP_SKB_CB(skb)->flags & TCPCB_FLAG_FIN)
                return 0;
 
+       if (tp->ca_state != TCP_CA_Open)
+               return 0;
+
        in_flight = tcp_packets_in_flight(tp);
 
        BUG_ON(tcp_skb_pcount(skb) <= 1 ||