tcp: add tcp_sock_set_user_timeout

Add a helper to directly set the TCP_USER_TIMEOUT sockopt from kernel
space without going through a fake uaccess.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

fs/ocfs2/cluster/tcp.c

@@ -1441,14 +1441,6 @@ static void o2net_rx_until_empty(struct work_struct *work)
 	sc_put(sc);
 }
 
-static int o2net_set_usertimeout(struct socket *sock)
-{
-	int user_timeout = O2NET_TCP_USER_TIMEOUT;
-
-	return kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
-				(void *)&user_timeout, sizeof(user_timeout));
-}
-
 static void o2net_initialize_handshake(void)
 {
 	o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
@@ -1629,12 +1621,7 @@ static void o2net_start_connect(struct work_struct *work)
 	}
 
 	tcp_sock_set_nodelay(sc->sc_sock->sk);
-
-	ret = o2net_set_usertimeout(sock);
-	if (ret) {
-		mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
-		goto out;
-	}
+	tcp_sock_set_user_timeout(sock->sk, O2NET_TCP_USER_TIMEOUT);
 
 	o2net_register_callbacks(sc->sc_sock->sk, sc);
 
@@ -1821,12 +1808,7 @@ static int o2net_accept_one(struct socket *sock, int *more)
 	new_sock->sk->sk_allocation = GFP_ATOMIC;
 
 	tcp_sock_set_nodelay(new_sock->sk);
-
-	ret = o2net_set_usertimeout(new_sock);
-	if (ret) {
-		mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
-		goto out;
-	}
+	tcp_sock_set_user_timeout(new_sock->sk, O2NET_TCP_USER_TIMEOUT);
 
 	ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin, 1);
 	if (ret < 0)

include/linux/tcp.h

@@ -501,5 +501,6 @@ void tcp_sock_set_cork(struct sock *sk, bool on);
 void tcp_sock_set_nodelay(struct sock *sk);
 void tcp_sock_set_quickack(struct sock *sk, int val);
 int tcp_sock_set_syncnt(struct sock *sk, int val);
+void tcp_sock_set_user_timeout(struct sock *sk, u32 val);
 
 #endif	/* _LINUX_TCP_H */

net/ipv4/tcp.c

@@ -2893,6 +2893,14 @@ int tcp_sock_set_syncnt(struct sock *sk, int val)
 }
 EXPORT_SYMBOL(tcp_sock_set_syncnt);
 
+void tcp_sock_set_user_timeout(struct sock *sk, u32 val)
+{
+	lock_sock(sk);
+	inet_csk(sk)->icsk_user_timeout = val;
+	release_sock(sk);
+}
+EXPORT_SYMBOL(tcp_sock_set_user_timeout);
+
 /*
  *	Socket option code for TCP.
  */

net/sunrpc/xprtsock.c

@@ -2115,8 +2115,7 @@ static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
 			(char *)&keepcnt, sizeof(keepcnt));
 
 	/* TCP user timeout (see RFC5482) */
-	kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
-			(char *)&timeo, sizeof(timeo));
+	tcp_sock_set_user_timeout(sock->sk, timeo);
 }
 
 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,