[NET] Generalise tcp_listen_opt

This chunks out the accept_queue and tcp_listen_opt code and moves
them to net/core/request_sock.c and include/net/request_sock.h, to
make it useful for other transport protocols, DCCP being the first one
to use it.

Next patches will rename tcp_listen_opt to accept_sock and remove the
inline tcp functions that just call a reqsk_queue_ function.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 0e6d525..b3943e7 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -790,10 +790,8 @@
 		newtp->probes_out = 0;
 		newtp->rx_opt.num_sacks = 0;
 		newtp->urg_data = 0;
-		newtp->listen_opt = NULL;
-		newtp->accept_queue = newtp->accept_queue_tail = NULL;
-		/* Deinitialize syn_wait_lock to trap illegal accesses. */
-		memset(&newtp->syn_wait_lock, 0, sizeof(newtp->syn_wait_lock));
+		/* Deinitialize accept_queue to trap illegal accesses. */
+		memset(&newtp->accept_queue, 0, sizeof(newtp->accept_queue));
 
 		/* Back to base struct sock members. */
 		newsk->sk_err = 0;