[NET] share tcp_v4_destroy_sock with tcpv6

tcp_v6_destroy_sock just extends tcp_v4_destroy_sock, so reuse the
tcp_v4_destroy_sock instead of cut'n'pasting it into tcpv6.
Signed-off-by: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
Signed-off-by: David S. Miller <davem@redhat.com>

net/ipv4/tcp_ipv4.c

@@ -2094,7 +2094,7 @@ static int tcp_v4_init_sock(struct sock *sk)
 	return 0;
 }
 
-static int tcp_v4_destroy_sock(struct sock *sk)
+int tcp_v4_destroy_sock(struct sock *sk)
 {
 	struct tcp_opt *tp = tcp_sk(sk);
 
@@ -2118,6 +2118,8 @@ static int tcp_v4_destroy_sock(struct sock *sk)
 	return 0;
 }
 
+EXPORT_SYMBOL(tcp_v4_destroy_sock);
+
 #ifdef CONFIG_PROC_FS
 /* Proc filesystem TCP sock list dumping. */
 

net/ipv6/tcp_ipv6.c

@@ -1892,25 +1892,9 @@ static int tcp_v6_init_sock(struct sock *sk)
 
 static int tcp_v6_destroy_sock(struct sock *sk)
 {
-	struct tcp_opt *tp = tcp_sk(sk);
-
-	tcp_clear_xmit_timers(sk);
-
-	/* Cleanup up the write buffer. */
-  	sk_stream_writequeue_purge(sk);
-
-	/* Cleans up our, hopefully empty, out_of_order_queue. */
-  	__skb_queue_purge(&tp->out_of_order_queue);
-
-	/* Clean prequeue, it must be empty really */
-	__skb_queue_purge(&tp->ucopy.prequeue);
-
-	/* Clean up a referenced TCP bind bucket. */
-	if (tcp_sk(sk)->bind_hash)
-		tcp_put_port(sk);
-
-	atomic_dec(&tcp_sockets_allocated);
+	extern int tcp_v4_destroy_sock(struct sock *sk);
 
+	tcp_v4_destroy_sock(sk);
 	return inet6_destroy_sock(sk);
 }