_copy_from_iter
return _copy_from_iter(addr, bytes, i);
len = _copy_from_iter(req->iu->buf, usr_len, &iter);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
return _copy_from_iter(addr, bytes, i);
EXPORT_SYMBOL(_copy_from_iter);
n = _copy_from_iter(kaddr + offset, n, i);