net: add sock_no_linger

Add a helper to directly set the SO_LINGER sockopt from kernel space
with onoff set to true and a linger time of 0 without going through a
fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/tcp_connect.c b/net/rds/tcp_connect.c
index 008f50f..4e64598 100644
--- a/net/rds/tcp_connect.c
+++ b/net/rds/tcp_connect.c
@@ -207,7 +207,7 @@ void rds_tcp_conn_path_shutdown(struct rds_conn_path *cp)
 
 	if (sock) {
 		if (rds_destroy_pending(cp->cp_conn))
-			rds_tcp_set_linger(sock);
+			sock_no_linger(sock->sk);
 		sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
 		lock_sock(sock->sk);
 		rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */