tcp: fixing TLP's FIN recovery

[ Upstream commit bef1909ee3ed1ca39231b260a8d3b4544ecd0c8f ]

Fix to a problem observed when losing a FIN segment that does not
contain data.  In such situations, TLP is unable to recover from
*any* tail loss and instead adds at least PTO ms to the
retransmission process, i.e., RTO = RTO + PTO.

Signed-off-by: Per Hurtig <per.hurtig@kau.se>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nandita Dukkipati <nanditad@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 62aff23d19d1c44078fbf5c660ba93c13270559f..11ef25c9cf43200548f5a75760adb2f509575124 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2036,9 +2036,7 @@ void tcp_send_loss_probe(struct sock *sk)
        if (WARN_ON(!skb || !tcp_skb_pcount(skb)))
                goto rearm_timer;
 
-       /* Probe with zero data doesn't trigger fast recovery. */
-       if (skb->len > 0)
-               err = __tcp_retransmit_skb(sk, skb);
+       err = __tcp_retransmit_skb(sk, skb);
 
        /* Record snd_nxt for loss detection. */
        if (likely(!err))