1 files changed, 23 insertions, 14 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 3d61c52bdf79..d463c35db33d 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1402,11 +1402,19 @@ static void tcp_cwnd_application_limited(struct sock *sk)
         tp->snd_cwnd_stamp = tcp_time_stamp;
 }
 
-static void tcp_cwnd_validate(struct sock *sk, u32 unsent_segs)
+static void tcp_cwnd_validate(struct sock *sk, bool is_cwnd_limited)
 {
         struct tcp_sock *tp = tcp_sk(sk);
 
-        tp->lsnd_pending = tp->packets_out + unsent_segs;
+        /* Track the maximum number of outstanding packets in each
+         * window, and remember whether we were cwnd-limited then.
+         */
+        if (!before(tp->snd_una, tp->max_packets_seq) ||
+            tp->packets_out > tp->max_packets_out) {
+                tp->max_packets_out = tp->packets_out;
+                tp->max_packets_seq = tp->snd_nxt;
+                tp->is_cwnd_limited = is_cwnd_limited;
+        }
 
         if (tcp_is_cwnd_limited(sk)) {
                 /* Network is feed fully. */
@@ -1660,7 +1668,8 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
  *
  * This algorithm is from John Heffner.
  */
-static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
+static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
+                                 bool *is_cwnd_limited)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         const struct inet_connection_sock *icsk = inet_csk(sk);
@@ -1724,6 +1733,9 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
         if (!tp->tso_deferred)
                 tp->tso_deferred = 1 | (jiffies << 1);
 
+        if (cong_win < send_win && cong_win < skb->len)
+                *is_cwnd_limited = true;
+
         return true;
 
 send_now:
@@ -1881,9 +1893,10 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct sk_buff *skb;
-        unsigned int tso_segs, sent_pkts, unsent_segs = 0;
+        unsigned int tso_segs, sent_pkts;
         int cwnd_quota;
         int result;
+        bool is_cwnd_limited = false;
 
         sent_pkts = 0;
 
@@ -1908,6 +1921,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 
                 cwnd_quota = tcp_cwnd_test(tp, skb);
                 if (!cwnd_quota) {
+                        is_cwnd_limited = true;
                         if (push_one == 2)
                                 /* Force out a loss probe pkt. */
                                 cwnd_quota = 1;
@@ -1924,8 +1938,9 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
                                                       nonagle : TCP_NAGLE_PUSH))))
                                 break;
                 } else {
-                        if (!push_one && tcp_tso_should_defer(sk, skb))
-                                goto compute_unsent_segs;
+                        if (!push_one &&
+                            tcp_tso_should_defer(sk, skb, &is_cwnd_limited))
+                                break;
                 }
 
                 /* TCP Small Queues :
@@ -1950,14 +1965,8 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
                          * there is no smp_mb__after_set_bit() yet
                          */
                         smp_mb__after_clear_bit();
-                        if (atomic_read(&sk->sk_wmem_alloc) > limit) {
-                                u32 unsent_bytes;
-
-compute_unsent_segs:
-                                unsent_bytes = tp->write_seq - tp->snd_nxt;
-                                unsent_segs = DIV_ROUND_UP(unsent_bytes, mss_now);
+                        if (atomic_read(&sk->sk_wmem_alloc) > limit)
                                 break;
-                        }
                 }
 
                 limit = mss_now;
@@ -1997,7 +2006,7 @@ repair:
                 /* Send one loss probe per tail loss episode. */
                 if (push_one != 2)
                         tcp_schedule_loss_probe(sk);
-                tcp_cwnd_validate(sk, unsent_segs);
+                tcp_cwnd_validate(sk, is_cwnd_limited);
                 return false;
         }
         return (push_one == 2) || (!tp->packets_out && tcp_send_head(sk));