[TCP]: Unconditionally clear TCP_NAGLE_PUSH in skb_entail().
Intention of this bit is to force pushing of the existing
send queue when TCP_CORK or TCP_NODELAY state changes via
setsockopt().
But it's easy to create a situation where the bit never
clears. For example, if the send queue starts empty:
1) set TCP_NODELAY
2) clear TCP_NODELAY
3) set TCP_CORK
4) do small write()
The current code will leave TCP_NAGLE_PUSH set after that
sequence. Unconditionally clearing the bit when new data
is added via skb_entail() solves the problem.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ddb6ce4..69b1fcf 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -584,7 +584,7 @@
sk_charge_skb(sk, skb);
if (!sk->sk_send_head)
sk->sk_send_head = skb;
- else if (tp->nonagle&TCP_NAGLE_PUSH)
+ if (tp->nonagle & TCP_NAGLE_PUSH)
tp->nonagle &= ~TCP_NAGLE_PUSH;
}