From c7f84b5723f1a60becd79d895ab214a7d5ee93c1 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 11 Jan 2023 14:28:57 +0000 Subject: [PATCH] mm: use entire_mapcount in __page_dup_rmap() Remove the use of the compound_mapcount_ptr() wrapper, and add an assertion that we're not passing a tail page if we're duplicating a PMD. Link: https://lkml.kernel.org/r/20230111142915.1001531-12-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- include/linux/rmap.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index aa682a2..a6bd1f0 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -208,7 +208,14 @@ void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, static inline void __page_dup_rmap(struct page *page, bool compound) { - atomic_inc(compound ? compound_mapcount_ptr(page) : &page->_mapcount); + if (compound) { + struct folio *folio = (struct folio *)page; + + VM_BUG_ON_PAGE(compound && !PageHead(page), page); + atomic_inc(&folio->_entire_mapcount); + } else { + atomic_inc(&page->_mapcount); + } } static inline void page_dup_file_rmap(struct page *page, bool compound) -- 2.7.4