From b2926ac8178bf5c88ada4285f413f56c1cafc592 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 11 Dec 2023 16:22:10 +0000 Subject: [PATCH] mm: remove stale example from comment folio_add_new_anon_rmap() no longer works this way, so just remove the entire example. Link: https://lkml.kernel.org/r/20231211162214.2146080-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: David Hildenbrand Cc: Ralph Campbell Signed-off-by: Andrew Morton --- mm/memremap.c | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) diff --git a/mm/memremap.c b/mm/memremap.c index 9531faa92a7c..9e9fb1972fff 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -473,21 +473,11 @@ void free_zone_device_page(struct page *page) __ClearPageAnonExclusive(page); /* - * When a device managed page is freed, the page->mapping field + * When a device managed page is freed, the folio->mapping field * may still contain a (stale) mapping value. For example, the - * lower bits of page->mapping may still identify the page as an - * anonymous page. Ultimately, this entire field is just stale - * and wrong, and it will cause errors if not cleared. One - * example is: - * - * migrate_vma_pages() - * migrate_vma_insert_page() - * page_add_new_anon_rmap() - * __page_set_anon_rmap() - * ...checks page->mapping, via PageAnon(page) call, - * and incorrectly concludes that the page is an - * anonymous page. Therefore, it incorrectly, - * silently fails to set up the new anon rmap. + * lower bits of folio->mapping may still identify the folio as an + * anonymous folio. Ultimately, this entire field is just stale + * and wrong, and it will cause errors if not cleared. * * For other types of ZONE_DEVICE pages, migration is either * handled differently or not done at all, so there is no need