From 74e8ee4708a8edabbbc7ab8c12ec24d7a561bb41 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Tue, 18 Jan 2022 10:50:48 -0500 Subject: mm: Turn head_compound_mapcount() into folio_entire_mapcount() Adjust documentation to be more clear. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig --- include/linux/mm.h | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index dede2eda4d7f..70f0ca217962 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -776,21 +776,26 @@ static inline int is_vmalloc_or_module_addr(const void *x) } #endif -static inline int head_compound_mapcount(struct page *head) +/* + * How many times the entire folio is mapped as a single unit (eg by a + * PMD or PUD entry). This is probably not what you want, except for + * debugging purposes; look at folio_mapcount() or page_mapcount() + * instead. + */ +static inline int folio_entire_mapcount(struct folio *folio) { - return atomic_read(compound_mapcount_ptr(head)) + 1; + VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); + return atomic_read(folio_mapcount_ptr(folio)) + 1; } /* * Mapcount of compound page as a whole, does not include mapped sub-pages. * - * Must be called only for compound pages or any their tail sub-pages. + * Must be called only for compound pages. */ static inline int compound_mapcount(struct page *page) { - VM_BUG_ON_PAGE(!PageCompound(page), page); - page = compound_head(page); - return head_compound_mapcount(page); + return folio_entire_mapcount(page_folio(page)); } /* -- cgit v1.2.3-71-gd317