SUNRPC: allow disabling idle timeout

In the gss-proxy case we don't want to have to reconnect at random--we
want to connect only on gss-proxy startup when we can steal gss-proxy's
context to do the connect in the right namespace.

So, provide a flag that allows the rpc_create caller to turn off the
idle timeout.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

include/linux/sunrpc/clnt.h

@@ -125,6 +125,7 @@ struct rpc_create_args {
 #define RPC_CLNT_CREATE_DISCRTRY	(1UL << 5)
 #define RPC_CLNT_CREATE_QUIET		(1UL << 6)
 #define RPC_CLNT_CREATE_INFINITE_SLOTS	(1UL << 7)
+#define RPC_CLNT_CREATE_NO_IDLE_TIMEOUT	(1UL << 8)
 
 struct rpc_clnt *rpc_create(struct rpc_create_args *args);
 struct rpc_clnt	*rpc_bind_new_program(struct rpc_clnt *,

include/linux/sunrpc/xprt.h

@@ -256,6 +256,7 @@ static inline int bc_prealloc(struct rpc_rqst *req)
 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 
 #define XPRT_CREATE_INFINITE_SLOTS	(1U)
+#define XPRT_CREATE_NO_IDLE_TIMEOUT	(1U << 1)
 
 struct xprt_create {
 	int			ident;		/* XPRT_TRANSPORT identifier */

net/sunrpc/clnt.c

@@ -416,6 +416,8 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 
 	if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 		xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
+	if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
+		xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 	/*
 	 * If the caller chooses not to specify a hostname, whip
 	 * up a string representation of the passed-in address.

net/sunrpc/xprt.c

@@ -1300,6 +1300,8 @@ struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
 				-PTR_ERR(xprt));
 		goto out;
 	}
+	if (args->flags & XPRT_CREATE_NO_IDLE_TIMEOUT)
+		xprt->idle_timeout = 0;
 	INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
 	if (xprt_has_timer(xprt))
 		setup_timer(&xprt->timer, xprt_init_autodisconnect,