linux-kernel - [PATCH v1] mm/huge_memory: fix folio_set_dirty() vs. folio_mark

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Date: Mon, 22 Jan 2024 18:54:07 +0100
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	David Hildenbrand <david@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Matthew Wilcox <willy@...radead.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH v1] mm/huge_memory: fix folio_set_dirty() vs. folio_mark_dirty()

The correct folio replacement for "set_page_dirty()" is
"folio_mark_dirty()", not "folio_set_dirty()". Using the latter won't
properly inform the FS using the dirty_folio() callback.

This has been found by code inspection, but likely this can result in
some real trouble.

Fixes: a8e61d584eda0 ("mm/huge_memory: page_remove_rmap() -> folio_remove_rmap_pmd()")
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: Matthew Wilcox (Oracle) <willy@...radead.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 mm/huge_memory.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 94ef5c02b4596..5f31e51f22356 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2437,7 +2437,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 			page = pmd_page(old_pmd);
 			folio = page_folio(page);
 			if (!folio_test_dirty(folio) && pmd_dirty(old_pmd))
-				folio_set_dirty(folio);
+				folio_mark_dirty(folio);
 			if (!folio_test_referenced(folio) && pmd_young(old_pmd))
 				folio_set_referenced(folio);
 			folio_remove_rmap_pmd(folio, page, vma);
@@ -3563,7 +3563,7 @@ int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
 	}
 
 	if (pmd_dirty(pmdval))
-		folio_set_dirty(folio);
+		folio_mark_dirty(folio);
 	if (pmd_write(pmdval))
 		entry = make_writable_migration_entry(page_to_pfn(page));
 	else if (anon_exclusive)
-- 
2.43.0