The quilt patch titled
Subject: mm: reimplement compound_order()
has been removed from the -mm tree. Its filename was
mm-reimplement-compound_order.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: reimplement compound_order()
Date: Wed, 11 Jan 2023 14:29:02 +0000
Make compound_order() use struct folio. It can't be turned into a wrapper
around folio_order() as a page can be turned into a tail page between a
check in compound_order() and the assertion in folio_test_large().
Link: https://lkml.kernel.org/r/20230111142915.1001531-17-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/include/linux/mm.h~mm-reimplement-compound_order
+++ a/include/linux/mm.h
@@ -719,11 +719,20 @@ int vma_is_stack_for_current(struct vm_a
struct mmu_gather;
struct inode;
+/*
+ * compound_order() can be called without holding a reference, which means
+ * that niceties like page_folio() don't work. These callers should be
+ * prepared to handle wild return values. For example, PG_head may be
+ * set before _folio_order is initialised, or this may be a tail page.
+ * See compaction.c for some good examples.
+ */
static inline unsigned int compound_order(struct page *page)
{
- if (!PageHead(page))
+ struct folio *folio = (struct folio *)page;
+
+ if (!test_bit(PG_head, &folio->flags))
return 0;
- return page[1].compound_order;
+ return folio->_folio_order;
}
/**
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
