[048/131] mm/page_alloc: restrict and formalize compound_page_dtors[]
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Message ID 20200603225917._dZfZ5SQB%akpm@linux-foundation.org
State New
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Series
  • [001/131] mm/slub: fix a memory leak in sysfs_slab_add()
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Commit Message

Andrew Morton June 3, 2020, 10:59 p.m. UTC
From: Anshuman Khandual <anshuman.khandual@arm.com>
Subject: mm/page_alloc: restrict and formalize compound_page_dtors[]

Restrict elements in compound_page_dtors[] array per NR_COMPOUND_DTORS and
explicitly position them according to enum compound_dtor_id.  This
improves protection against possible misalignment between
compound_page_dtors[] and enum compound_dtor_id later on.

Link: http://lkml.kernel.org/r/1589795958-19317-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm.h |    2 +-
 mm/page_alloc.c    |   10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

Patch
diff mbox series

--- a/include/linux/mm.h~mm-page_alloc-restrict-and-formalize-compound_page_dtors
+++ a/include/linux/mm.h
@@ -867,7 +867,7 @@  enum compound_dtor_id {
 #endif
 	NR_COMPOUND_DTORS,
 };
-extern compound_page_dtor * const compound_page_dtors[];
+extern compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS];
 
 static inline void set_compound_page_dtor(struct page *page,
 		enum compound_dtor_id compound_dtor)
--- a/mm/page_alloc.c~mm-page_alloc-restrict-and-formalize-compound_page_dtors
+++ a/mm/page_alloc.c
@@ -302,14 +302,14 @@  const char * const migratetype_names[MIG
 #endif
 };
 
-compound_page_dtor * const compound_page_dtors[] = {
-	NULL,
-	free_compound_page,
+compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
+	[NULL_COMPOUND_DTOR] = NULL,
+	[COMPOUND_PAGE_DTOR] = free_compound_page,
 #ifdef CONFIG_HUGETLB_PAGE
-	free_huge_page,
+	[HUGETLB_PAGE_DTOR] = free_huge_page,
 #endif
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	free_transhuge_page,
+	[TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
 #endif
 };