static int nfs4_init_callback(struct nfs_client *clp)
{
	struct rpc_xprt *xprt;
	int error;

	xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);

	if (nfs4_has_session(clp)) {
		error = xprt_setup_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
		if (error < 0)
			return error;
	}

	error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
	if (error < 0) {
		dprintk("%s: failed to start callback. Error = %d\n",
			__func__, error);
		return error;
	}
	__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);

	return 0;
}
static int nfs4_init_callback(struct nfs_client *clp)
{
	struct rpc_xprt *xprt;
	int error;

	xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);

	if (nfs4_has_session(clp)) {
		error = xprt_setup_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
		if (error < 0)
			return error;
	}

	error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
	if (error < 0) {
		dprintk("%s: failed to start callback. Error = %d\n",
			__func__, error);
		return error;
	}
	__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);

	return 0;
}