1 files changed, 14 insertions, 9 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index b85bc7c3736a..b61274b666f6 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2800,8 +2800,8 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
         tcp_xmit_retransmit_queue(sk);
 }
 
-static inline void tcp_ack_update_rtt(struct sock *sk, const int flag,
-                                      s32 seq_rtt)
+static inline bool tcp_ack_update_rtt(struct sock *sk, const int flag,
+                                      s32 seq_rtt, s32 sack_rtt)
 {
         const struct tcp_sock *tp = tcp_sk(sk);
 
@@ -2813,6 +2813,9 @@ static inline void tcp_ack_update_rtt(struct sock *sk, const int flag,
         if (flag & FLAG_RETRANS_DATA_ACKED)
                 seq_rtt = -1;
 
+        if (seq_rtt < 0)
+                seq_rtt = sack_rtt;
+
         /* RTTM Rule: A TSecr value received in a segment is used to
          * update the averaged RTT measurement only if the segment
          * acknowledges some new data, i.e., only if it advances the
@@ -2823,13 +2826,14 @@ static inline void tcp_ack_update_rtt(struct sock *sk, const int flag,
                 seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
 
         if (seq_rtt < 0)
-                return;
+                return false;
 
         tcp_rtt_estimator(sk, seq_rtt);
         tcp_set_rto(sk);
 
         /* RFC6298: only reset backoff on valid RTT measurement. */
         inet_csk(sk)->icsk_backoff = 0;
+        return true;
 }
 
 /* Compute time elapsed between (last) SYNACK and the ACK completing 3WHS. */
@@ -2840,7 +2844,7 @@ static void tcp_synack_rtt_meas(struct sock *sk, struct request_sock *req)
 
         if (tp->lsndtime && !tp->total_retrans)
                 seq_rtt = tcp_time_stamp - tp->lsndtime;
-        tcp_ack_update_rtt(sk, FLAG_SYN_ACKED, seq_rtt);
+        tcp_ack_update_rtt(sk, FLAG_SYN_ACKED, seq_rtt, -1);
 }
 
 static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
@@ -2929,7 +2933,7 @@ static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb)
  * arrived at the other end.
  */
 static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
-                               u32 prior_snd_una)
+                               u32 prior_snd_una, s32 sack_rtt)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         const struct inet_connection_sock *icsk = inet_csk(sk);
@@ -3019,6 +3023,10 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
         if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
                 flag |= FLAG_SACK_RENEGING;
 
+        if (tcp_ack_update_rtt(sk, flag, seq_rtt, sack_rtt) ||
+            (flag & FLAG_ACKED))
+                tcp_rearm_rto(sk);
+
         if (flag & FLAG_ACKED) {
                 const struct tcp_congestion_ops *ca_ops
                         = inet_csk(sk)->icsk_ca_ops;
@@ -3028,9 +3036,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
                         tcp_mtup_probe_success(sk);
                 }
 
-                tcp_ack_update_rtt(sk, flag, seq_rtt);
-                tcp_rearm_rto(sk);
-
                 if (tcp_is_reno(tp)) {
                         tcp_remove_reno_sacks(sk, pkts_acked);
                 } else {
@@ -3339,7 +3344,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
         /* See if we can take anything off of the retransmit queue. */
         acked = tp->packets_out;
-        flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una);
+        flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una, sack_rtt);
         acked -= tp->packets_out;
 
         if (tcp_ack_is_dubious(sk, flag)) {