dofilereadv
return (dofilereadv(p, SCARG(uap, fd), &auio, 0, retval));
error = dofilereadv(p, SCARG(uap, fd), &auio, 0, retval);
return (dofilereadv(p, SCARG(uap, fd), &auio, FO_POSITION, retval));
error = dofilereadv(p, SCARG(uap, fd), &auio, FO_POSITION, retval);
int dofilereadv(struct proc *, int, struct uio *, int, register_t *);