1 files changed, 7 insertions, 5 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index da782e7ab16d..e72af7e31d1c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2659,7 +2659,7 @@ static void DBGUNDO(struct sock *sk, const char *msg)
 #define DBGUNDO(x...) do { } while (0)
 #endif
 
-static void tcp_undo_cwr(struct sock *sk, const int undo)
+static void tcp_undo_cwr(struct sock *sk, const int undo_ssthresh)
 {
         struct tcp_sock *tp = tcp_sk(sk);
 
@@ -2671,14 +2671,13 @@ static void tcp_undo_cwr(struct sock *sk, const int undo)
                 else
                         tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1);
 
-                if (undo && tp->prior_ssthresh > tp->snd_ssthresh) {
+                if (undo_ssthresh && tp->prior_ssthresh > tp->snd_ssthresh) {
                         tp->snd_ssthresh = tp->prior_ssthresh;
                         TCP_ECN_withdraw_cwr(tp);
                 }
         } else {
                 tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh);
         }
-        tcp_moderate_cwnd(tp);
         tp->snd_cwnd_stamp = tcp_time_stamp;
 }
 
@@ -2822,8 +2821,11 @@ static int tcp_try_undo_loss(struct sock *sk)
 static inline void tcp_complete_cwr(struct sock *sk)
 {
         struct tcp_sock *tp = tcp_sk(sk);
-        tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
-        tp->snd_cwnd_stamp = tcp_time_stamp;
+        /* Do not moderate cwnd if it's already undone in cwr or recovery */
+        if (tp->undo_marker && tp->snd_cwnd > tp->snd_ssthresh) {
+                tp->snd_cwnd = tp->snd_ssthresh;
+                tp->snd_cwnd_stamp = tcp_time_stamp;
+        }
         tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR);
 }