1 files changed, 21 insertions, 23 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9550cc42de2d..ff71b18d9682 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -508,9 +508,6 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
 	u32 new_sample = tp->rcv_rtt_est.rtt_us;
 	long m = sample;
 
-	if (m == 0)
-		m = 1;
-
 	if (new_sample != 0) {
 		/* If we sample in larger samples in the non-timestamp
 		 * case, we could grossly overestimate the RTT especially
@@ -547,6 +544,8 @@ static inline void tcp_rcv_rtt_measure(struct tcp_sock *tp)
 	if (before(tp->rcv_nxt, tp->rcv_rtt_est.seq))
 		return;
 	delta_us = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcv_rtt_est.time);
+	if (!delta_us)
+		delta_us = 1;
 	tcp_rcv_rtt_update(tp, delta_us, 1);
 
 new_measure:
@@ -563,8 +562,11 @@ static inline void tcp_rcv_rtt_measure_ts(struct sock *sk,
 	    (TCP_SKB_CB(skb)->end_seq -
 	     TCP_SKB_CB(skb)->seq >= inet_csk(sk)->icsk_ack.rcv_mss)) {
 		u32 delta = tcp_time_stamp(tp) - tp->rx_opt.rcv_tsecr;
-		u32 delta_us = delta * (USEC_PER_SEC / TCP_TS_HZ);
+		u32 delta_us;
 
+		if (!delta)
+			delta = 1;
+		delta_us = delta * (USEC_PER_SEC / TCP_TS_HZ);
 		tcp_rcv_rtt_update(tp, delta_us, 0);
 	}
 }
@@ -576,8 +578,8 @@ static inline void tcp_rcv_rtt_measure_ts(struct sock *sk,
 void tcp_rcv_space_adjust(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	u32 copied;
 	int time;
-	int copied;
 
 	tcp_mstamp_refresh(tp);
 	time = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcvq_space.time);
@@ -600,38 +602,31 @@ void tcp_rcv_space_adjust(struct sock *sk)
 
 	if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf &&
 	    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
-		int rcvwin, rcvmem, rcvbuf;
+		int rcvmem, rcvbuf;
+		u64 rcvwin, grow;
 
 		/* minimal window to cope with packet losses, assuming
 		 * steady state. Add some cushion because of small variations.
 		 */
-		rcvwin = (copied << 1) + 16 * tp->advmss;
+		rcvwin = ((u64)copied << 1) + 16 * tp->advmss;
 
-		/* If rate increased by 25%,
-		 *	assume slow start, rcvwin = 3 * copied
-		 * If rate increased by 50%,
-		 *	assume sender can use 2x growth, rcvwin = 4 * copied
-		 */
-		if (copied >=
-		    tp->rcvq_space.space + (tp->rcvq_space.space >> 2)) {
-			if (copied >=
-			    tp->rcvq_space.space + (tp->rcvq_space.space >> 1))
-				rcvwin <<= 1;
-			else
-				rcvwin += (rcvwin >> 1);
-		}
+		/* Accommodate for sender rate increase (eg. slow start) */
+		grow = rcvwin * (copied - tp->rcvq_space.space);
+		do_div(grow, tp->rcvq_space.space);
+		rcvwin += (grow << 1);
 
 		rcvmem = SKB_TRUESIZE(tp->advmss + MAX_TCP_HEADER);
 		while (tcp_win_from_space(sk, rcvmem) < tp->advmss)
 			rcvmem += 128;
 
-		rcvbuf = min(rcvwin / tp->advmss * rcvmem,
-			     sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
+		do_div(rcvwin, tp->advmss);
+		rcvbuf = min_t(u64, rcvwin * rcvmem,
+			       sock_net(sk)->ipv4.sysctl_tcp_rmem[2]);
 		if (rcvbuf > sk->sk_rcvbuf) {
 			sk->sk_rcvbuf = rcvbuf;
 
 			/* Make the window clamp follow along.  */
-			tp->window_clamp = rcvwin;
+			tp->window_clamp = tcp_win_from_space(sk, rcvbuf);
 		}
 	}
 	tp->rcvq_space.space = copied;
@@ -5304,6 +5299,9 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 	unsigned int len = skb->len;
 	struct tcp_sock *tp = tcp_sk(sk);
 
+	/* TCP congestion window tracking */
+	trace_tcp_probe(sk, skb);
+
 	tcp_mstamp_refresh(tp);
 	if (unlikely(!sk->sk_rx_dst))
 		inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb);