Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Conflicts were simply overlapping changes.  In the net/ipv4/route.c
case the code had simply moved around a little bit and the same fix
was made in both 'net' and 'net-next'.

In the net/sched/sch_generic.c case a fix in 'net' happened at
the same time that a new argument was added to qdisc_hash_add().

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

1 files changed, 12 insertions, 8 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 31f2765ef851..a5838858c362 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1935,6 +1935,7 @@ void tcp_enter_loss(struct sock *sk)
         struct tcp_sock *tp = tcp_sk(sk);
         struct net *net = sock_net(sk);
         struct sk_buff *skb;
+        bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery;
         bool is_reneg;                  /* is receiver reneging on SACKs? */
         bool mark_lost;
 
@@ -1994,15 +1995,18 @@ void tcp_enter_loss(struct sock *sk)
         tp->high_seq = tp->snd_nxt;
         tcp_ecn_queue_cwr(tp);
 
-        /* F-RTO RFC5682 sec 3.1 step 1 mandates to disable F-RTO
-         * if a previous recovery is underway, otherwise it may incorrectly
-         * call a timeout spurious if some previously retransmitted packets
-         * are s/acked (sec 3.2). We do not apply that retriction since
-         * retransmitted skbs are permanently tagged with TCPCB_EVER_RETRANS
-         * so FLAG_ORIG_SACK_ACKED is always correct. But we do disable F-RTO
-         * on PTMU discovery to avoid sending new data.
+        /* F-RTO RFC5682 sec 3.1 step 1: retransmit SND.UNA if no previous
+         * loss recovery is underway except recurring timeout(s) on
+         * the same SND.UNA (sec 3.2). Disable F-RTO on path MTU probing
+         *
+         * In theory F-RTO can be used repeatedly during loss recovery.
+         * In practice this interacts badly with broken middle-boxes that
+         * falsely raise the receive window, which results in repeated
+         * timeouts and stop-and-go behavior.
          */
-        tp->frto = sysctl_tcp_frto && !inet_csk(sk)->icsk_mtup.probe_size;
+        tp->frto = sysctl_tcp_frto &&
+                   (new_recovery || icsk->icsk_retransmits) &&
+                   !inet_csk(sk)->icsk_mtup.probe_size;
 }
 
 /* If ACK arrived pointing to a remembered SACK, it means that our