SUNRPC: Allow specification of TCP client connect timeout at setup

When we create a TCP transport, the connect timeout parameters are
currently fixed to be 90s. This is problematic in the pNFS flexfiles
case, where we may have multiple mirrors, and we would like to fail over
quickly to the next mirror if a data server is down.

This patch adds the ability to specify the connection parameters at RPC
client creation time.

Signed-off-by: Trond Myklebust <[e-mail]>
Signed-off-by: Anna Schumaker <[e-mail]>

include/linux/sunrpc/clnt.h

···
 	const struct cred	*cred;
 	unsigned int		max_connect;
 	struct xprtsec_parms	xprtsec;
+	unsigned long		connect_timeout;
+	unsigned long		reconnect_timeout;
 };
 
 struct rpc_add_xprt_test {

include/linux/sunrpc/xprt.h

···
 	struct rpc_xprt_switch	*bc_xps;
 	unsigned int		flags;
 	struct xprtsec_parms	xprtsec;
+	unsigned long		connect_timeout;
+	unsigned long		reconnect_timeout;
 };
 
 struct xprt_class {

net/sunrpc/clnt.c

···
 		.servername = args->servername,
 		.bc_xprt = args->bc_xprt,
 		.xprtsec = args->xprtsec,
+		.connect_timeout = args->connect_timeout,
+		.reconnect_timeout = args->reconnect_timeout,
 	};
 	char servername[48];
 	struct rpc_clnt *clnt;

net/sunrpc/xprtsock.c

···
 		unsigned long reconnect_timeout)
 {
 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
-	struct rpc_timeout to;
-	unsigned long initval;
 
 	spin_lock(&xprt->transport_lock);
 	if (reconnect_timeout < xprt->max_reconnect_timeout)
···
 	xprt->timeout = &xs_tcp_default_timeout;
 
 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
+	if (args->reconnect_timeout)
+		xprt->max_reconnect_timeout = args->reconnect_timeout;
+
 	xprt->connect_timeout = xprt->timeout->to_initval *
 		(xprt->timeout->to_retries + 1);
+	if (args->connect_timeout)
+		xs_tcp_do_set_connect_timeout(xprt, args->connect_timeout);
 
 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
 	INIT_WORK(&transport->error_worker, xs_error_handle);