Make tcp adapt to the limited socket backlog change.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
                        if (!tcp_prequeue(sk, skb))
                                ret = tcp_v4_do_rcv(sk, skb);
                }
-       } else
-               sk_add_backlog(sk, skb);
+       } else if (sk_add_backlog_limited(sk, skb)) {
+               bh_unlock_sock(sk);
+               goto discard_and_relse;
+       }
        bh_unlock_sock(sk);
 
        sock_put(sk);
 
                        if (!tcp_prequeue(sk, skb))
                                ret = tcp_v6_do_rcv(sk, skb);
                }
-       } else
-               sk_add_backlog(sk, skb);
+       } else if (sk_add_backlog_limited(sk, skb)) {
+               bh_unlock_sock(sk);
+               goto discard_and_relse;
+       }
        bh_unlock_sock(sk);
 
        sock_put(sk);