[TCP]: Fix __tcp_push_pending_frames() 'nonagle' handling.

'nonagle' should be passed to the tcp_snd_test() function
as 'TCP_NAGLE_PUSH' if we are checking an SKB not at the
tail of the write_queue.  This is because Nagle does not
apply to such frames since we cannot possibly tack more
data onto them.

However, while doing this __tcp_push_pending_frames() makes
all of the packets in the write_queue use this modified
'nonagle' value.

Fix the bug and simplify this function by just calling
tcp_write_xmit() directly if sk_send_head is non-NULL.

As a result, we can now make tcp_data_snd_check() just call
tcp_push_pending_frames() instead of the specialized
__tcp_data_snd_check().

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 14 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e292e11c7319..ce1d7cfbecfc 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -894,24 +894,11 @@ void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp,
         struct sk_buff *skb = sk->sk_send_head;
 
         if (skb) {
-                if (!tcp_skb_is_last(sk, skb))
-                        nonagle = TCP_NAGLE_PUSH;
-                if (!tcp_snd_test(sk, skb, cur_mss, nonagle) ||
-                    tcp_write_xmit(sk, cur_mss, nonagle))
+                if (tcp_write_xmit(sk, cur_mss, nonagle))
                         tcp_check_probe_timer(sk, tp);
         }
 }
 
-void __tcp_data_snd_check(struct sock *sk, struct sk_buff *skb)
-{
-        struct tcp_sock *tp = tcp_sk(sk);
-
-        if (after(TCP_SKB_CB(skb)->end_seq, tp->snd_una + tp->snd_wnd) ||
-            tcp_packets_in_flight(tp) >= tp->snd_cwnd ||
-            tcp_write_xmit(sk, tcp_current_mss(sk, 1), tp->nonagle))
-                tcp_check_probe_timer(sk, tp);
-}
-
 /* This function returns the amount that we can raise the
  * usable window based on the following constraints
  *