ncl_readrpc
int ncl_readrpc(struct vnode *, struct uio *, struct ucred *);
error = ncl_readrpc(vp, uiop, cr);
error = ncl_readrpc(vp, &uio, cred);
return ncl_readrpc(vp, uio, cred);
error = ncl_readrpc(vp, &auio, ap->a_cred);