tcp: Allow send-limited cwnd to grow up to max_burst when gso disabled

This changes the logic in tcp_is_cwnd_limited() so that cwnd may grow
up to tcp_max_burst() even when sk_can_gso() is false, or when
sysctl_tcp_tso_win_divisor != 0.

Signed-off-by: John Heffner <johnwheffner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 7 deletions

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 3a6be23d222f..bfb1996bd99f 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -285,14 +285,11 @@ int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
         if (in_flight >= tp->snd_cwnd)
                 return 1;
 
-        if (!sk_can_gso(sk))
-                return 0;
-
         left = tp->snd_cwnd - in_flight;
-        if (sysctl_tcp_tso_win_divisor)
-                return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
-        else
-                return left <= tcp_max_burst(tp);
+        if (sk_can_gso(sk) &&
+            left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd)
+                return 1;
+        return left <= tcp_max_burst(tp);
 }
 EXPORT_SYMBOL_GPL(tcp_is_cwnd_limited);