Re: [PATCH] mm/hugetlb: get rid of page_hstate()

[Matthew Wilcox]

On Wed, Jul 19, 2023 at 10:59:44AM -0700, Sidhartha Kumar wrote:
> -			skip_pages = compound_nr(head) - (page - head);
> +			skip_pages = folio_nr_pages(folio) - (page - &folio->page);

It turns out that you can't do (page - head) under all configs.  It
works on all common ones, but the safe way to do what you want here is:

			skip_pages = folio_nr_pages(folio) -
					folio_page_idx(folio, page);