1 files changed, 26 insertions, 23 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b1c218df2c85..444ab5beecbd 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -163,7 +163,6 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	const u32 now = tcp_time_stamp;
-	const struct dst_entry *dst = __sk_dst_get(sk);
 
 	if (sysctl_tcp_slow_start_after_idle &&
 	    (!tp->packets_out && (s32)(now - tp->lsndtime) > icsk->icsk_rto))
@@ -174,9 +173,8 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
 	/* If it is a reply for ato after last received
 	 * packet, enter pingpong mode.
 	 */
-	if ((u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato &&
-	    (!dst || !dst_metric(dst, RTAX_QUICKACK)))
-			icsk->icsk_ack.pingpong = 1;
+	if ((u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato)
+		icsk->icsk_ack.pingpong = 1;
 }
 
 /* Account for an ACK we sent. */
@@ -1776,7 +1774,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 		goto send_now;
 
-	if (!((1 << icsk->icsk_ca_state) & (TCPF_CA_Open | TCPF_CA_CWR)))
+	if (icsk->icsk_ca_state >= TCP_CA_Recovery)
 		goto send_now;
 
 	/* Avoid bursty behavior by allowing defer
@@ -2151,7 +2149,7 @@ repair:
 		tcp_cwnd_validate(sk, is_cwnd_limited);
 		return false;
 	}
-	return (push_one == 2) || (!tp->packets_out && tcp_send_head(sk));
+	return !tp->packets_out && tcp_send_head(sk);
 }
 
 bool tcp_schedule_loss_probe(struct sock *sk)
@@ -2228,7 +2226,7 @@ static bool skb_still_in_host_queue(const struct sock *sk,
 	return false;
 }
 
-/* When probe timeout (PTO) fires, send a new segment if one exists, else
+/* When probe timeout (PTO) fires, try send a new segment if possible, else
  * retransmit the last segment.
  */
 void tcp_send_loss_probe(struct sock *sk)
@@ -2237,11 +2235,19 @@ void tcp_send_loss_probe(struct sock *sk)
 	struct sk_buff *skb;
 	int pcount;
 	int mss = tcp_current_mss(sk);
-	int err = -1;
 
-	if (tcp_send_head(sk)) {
-		err = tcp_write_xmit(sk, mss, TCP_NAGLE_OFF, 2, GFP_ATOMIC);
-		goto rearm_timer;
+	skb = tcp_send_head(sk);
+	if (skb) {
+		if (tcp_snd_wnd_test(tp, skb, mss)) {
+			pcount = tp->packets_out;
+			tcp_write_xmit(sk, mss, TCP_NAGLE_OFF, 2, GFP_ATOMIC);
+			if (tp->packets_out > pcount)
+				goto probe_sent;
+			goto rearm_timer;
+		}
+		skb = tcp_write_queue_prev(sk, skb);
+	} else {
+		skb = tcp_write_queue_tail(sk);
 	}
 
 	/* At most one outstanding TLP retransmission. */
@@ -2249,7 +2255,6 @@ void tcp_send_loss_probe(struct sock *sk)
 		goto rearm_timer;
 
 	/* Retransmit last segment. */
-	skb = tcp_write_queue_tail(sk);
 	if (WARN_ON(!skb))
 		goto rearm_timer;
 
@@ -2264,26 +2269,24 @@ void tcp_send_loss_probe(struct sock *sk)
 		if (unlikely(tcp_fragment(sk, skb, (pcount - 1) * mss, mss,
 					  GFP_ATOMIC)))
 			goto rearm_timer;
-		skb = tcp_write_queue_tail(sk);
+		skb = tcp_write_queue_next(sk, skb);
 	}
 
 	if (WARN_ON(!skb || !tcp_skb_pcount(skb)))
 		goto rearm_timer;
 
-	err = __tcp_retransmit_skb(sk, skb);
+	if (__tcp_retransmit_skb(sk, skb))
+		goto rearm_timer;
 
 	/* Record snd_nxt for loss detection. */
-	if (likely(!err))
-		tp->tlp_high_seq = tp->snd_nxt;
+	tp->tlp_high_seq = tp->snd_nxt;
 
+probe_sent:
+	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPLOSSPROBES);
+	/* Reset s.t. tcp_rearm_rto will restart timer from now */
+	inet_csk(sk)->icsk_pending = 0;
 rearm_timer:
-	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
-				  inet_csk(sk)->icsk_rto,
-				  TCP_RTO_MAX);
-
-	if (likely(!err))
-		NET_INC_STATS_BH(sock_net(sk),
-				 LINUX_MIB_TCPLOSSPROBES);
+	tcp_rearm_rto(sk);
 }
 
 /* Push out any pending frames which were held back due to