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-rw-r--r--net/ipv4/tcp_input.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4b255fe999d..41163ddc312 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1851,19 +1851,22 @@ static inline u32 tcp_cwnd_min(const struct sock *sk)
}
/* Decrease cwnd each second ack. */
-static void tcp_cwnd_down(struct sock *sk)
+static void tcp_cwnd_down(struct sock *sk, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
int decr = tp->snd_cwnd_cnt + 1;
- tp->snd_cwnd_cnt = decr&1;
- decr >>= 1;
+ if ((flag&FLAG_FORWARD_PROGRESS) ||
+ (IsReno(tp) && !(flag&FLAG_NOT_DUP))) {
+ tp->snd_cwnd_cnt = decr&1;
+ decr >>= 1;
- if (decr && tp->snd_cwnd > tcp_cwnd_min(sk))
- tp->snd_cwnd -= decr;
+ if (decr && tp->snd_cwnd > tcp_cwnd_min(sk))
+ tp->snd_cwnd -= decr;
- tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)+1);
- tp->snd_cwnd_stamp = tcp_time_stamp;
+ tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)+1);
+ tp->snd_cwnd_stamp = tcp_time_stamp;
+ }
}
/* Nothing was retransmitted or returned timestamp is less
@@ -2060,7 +2063,7 @@ static void tcp_try_to_open(struct sock *sk, int flag)
}
tcp_moderate_cwnd(tp);
} else {
- tcp_cwnd_down(sk);
+ tcp_cwnd_down(sk, flag);
}
}
@@ -2260,7 +2263,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
if (is_dupack || tcp_head_timedout(sk))
tcp_update_scoreboard(sk);
- tcp_cwnd_down(sk);
+ tcp_cwnd_down(sk, flag);
tcp_xmit_retransmit_queue(sk);
}