iov_iter_single_seg_count
linear = iov_iter_single_seg_count(it);
return min_t(size_t, iov_iter_single_seg_count(&req->iter),
return min(iov_iter_single_seg_count(ii), max_size);
size_t iov_iter_single_seg_count(const struct iov_iter *i);
EXPORT_SYMBOL(iov_iter_single_seg_count);
len = iov_iter_single_seg_count(data);