[PATCH] kNFSd: Make sure an early close on a nfs/tcp connection is handled properly.

From: Hirokazu Takahashi <taka@valinux.co.jp>

In svc_tcp_listen_data_ready we should be waiting for
TCP_LISTEN, not TCP_ESTABLISHED.  The later only worked
by accident.

Also, if a socket is closed as soon as we accept it, we
must shut it down straight away as we will never get a 'close'
event.

net/sunrpc/svcsock.c

@@ -681,8 +681,17 @@ svc_tcp_listen_data_ready(struct sock *sk, int count_unused)
 	dprintk("svc: socket %p TCP (listen) state change %d\n",
 			sk, sk->sk_state);
 
-	if  (sk->sk_state != TCP_ESTABLISHED) {
-		/* Aborted connection, SYN_RECV or whatever... */
+	if  (sk->sk_state != TCP_LISTEN) {
+		/*
+		 * This callback may called twice when a new connection
+		 * is established as a child socket inherits everything
+		 * from a parent LISTEN socket.
+		 * 1) data_ready method of the parent socket will be called
+		 *    when one of child sockets become ESTABLISHED.
+		 * 2) data_ready method of the child socket may be called
+		 *    when it receives data before the socket is accepted.
+		 * In case of 2, we should ignore it silently.
+		 */
 		goto out;
 	}
 	if (!(svsk = (struct svc_sock *) sk->sk_user_data)) {
@@ -1060,6 +1069,8 @@ svc_tcp_init(struct svc_sock *svsk)
 
 		set_bit(SK_CHNGBUF, &svsk->sk_flags);
 		set_bit(SK_DATA, &svsk->sk_flags);
+		if (sk->sk_state != TCP_ESTABLISHED) 
+			set_bit(SK_CLOSE, &svsk->sk_flags);
 	}
 }