4 files changed, 18 insertions, 7 deletions

diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index dde671e97829..c248e0dccbe1 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -80,7 +80,7 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 
         iph->version    =       4;
         iph->ihl        =       sizeof(struct iphdr) >> 2;
-        iph->frag_off   =       df;
+        iph->frag_off   =       ip_mtu_locked(&rt->dst) ? 0 : df;
         iph->protocol   =       proto;
         iph->tos        =       tos;
         iph->daddr      =       dst;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2868ef28ce52..1e37c1388189 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4268,7 +4268,7 @@ static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq)
          * If the sack array is full, forget about the last one.
          */
         if (this_sack >= TCP_NUM_SACKS) {
-                if (tp->compressed_ack)
+                if (tp->compressed_ack > TCP_FASTRETRANS_THRESH)
                         tcp_send_ack(sk);
                 this_sack--;
                 tp->rx_opt.num_sacks--;
@@ -4363,6 +4363,7 @@ static bool tcp_try_coalesce(struct sock *sk,
         if (TCP_SKB_CB(from)->has_rxtstamp) {
                 TCP_SKB_CB(to)->has_rxtstamp = true;
                 to->tstamp = from->tstamp;
+                skb_hwtstamps(to)->hwtstamp = skb_hwtstamps(from)->hwtstamp;
         }
 
         return true;
@@ -5188,7 +5189,17 @@ send_now:
         if (!tcp_is_sack(tp) ||
             tp->compressed_ack >= sock_net(sk)->ipv4.sysctl_tcp_comp_sack_nr)
                 goto send_now;
-        tp->compressed_ack++;
+
+        if (tp->compressed_ack_rcv_nxt != tp->rcv_nxt) {
+                tp->compressed_ack_rcv_nxt = tp->rcv_nxt;
+                if (tp->compressed_ack > TCP_FASTRETRANS_THRESH)
+                        NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPACKCOMPRESSED,
+                                      tp->compressed_ack - TCP_FASTRETRANS_THRESH);
+                tp->compressed_ack = 0;
+        }
+
+        if (++tp->compressed_ack <= TCP_FASTRETRANS_THRESH)
+                goto send_now;
 
         if (hrtimer_is_queued(&tp->compressed_ack_timer))
                 return;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 9c34b97d365d..3f510cad0b3e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -180,10 +180,10 @@ static inline void tcp_event_ack_sent(struct sock *sk, unsigned int pkts,
 {
         struct tcp_sock *tp = tcp_sk(sk);
 
-        if (unlikely(tp->compressed_ack)) {
+        if (unlikely(tp->compressed_ack > TCP_FASTRETRANS_THRESH)) {
                 NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPACKCOMPRESSED,
-                              tp->compressed_ack);
-                tp->compressed_ack = 0;
+                              tp->compressed_ack - TCP_FASTRETRANS_THRESH);
+                tp->compressed_ack = TCP_FASTRETRANS_THRESH;
                 if (hrtimer_try_to_cancel(&tp->compressed_ack_timer) == 1)
                         __sock_put(sk);
         }
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 676020663ce8..5f8b6d3cd855 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -740,7 +740,7 @@ static enum hrtimer_restart tcp_compressed_ack_kick(struct hrtimer *timer)
 
         bh_lock_sock(sk);
         if (!sock_owned_by_user(sk)) {
-                if (tp->compressed_ack)
+                if (tp->compressed_ack > TCP_FASTRETRANS_THRESH)
                         tcp_send_ack(sk);
         } else {
                 if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED,