2 files changed, 18 insertions, 7 deletions

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 179609d1d1ea..ff40e1d08157 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -315,7 +315,7 @@ int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 
 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 
-#define TCP_PINGPONG_THRESH     1
+#define TCP_PINGPONG_THRESH     3
 
 static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 {
@@ -331,4 +331,12 @@ static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 {
         return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 }
+
+static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
+{
+        struct inet_connection_sock *icsk = inet_csk(sk);
+
+        if (icsk->icsk_ack.pingpong < U8_MAX)
+                icsk->icsk_ack.pingpong++;
+}
 #endif /* _INET_CONNECTION_SOCK_H */
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 06228e2d010e..96bdb8eae9bb 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -165,13 +165,16 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
         if (tcp_packets_in_flight(tp) == 0)
                 tcp_ca_event(sk, CA_EVENT_TX_START);
 
-        tp->lsndtime = now;
-
-        /* If it is a reply for ato after last received
-         * packet, enter pingpong mode.
+        /* If this is the first data packet sent in response to the
+         * previous received data,
+         * and it is a reply for ato after last received packet,
+         * increase pingpong count.
          */
-        if ((u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato)
-                inet_csk_enter_pingpong_mode(sk);
+        if (before(tp->lsndtime, icsk->icsk_ack.lrcvtime) &&
+            (u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato)
+                inet_csk_inc_pingpong_cnt(sk);
+
+        tp->lsndtime = now;
 }
 
 /* Account for an ACK we sent. */