From: Anshuman Khandual <anshuman.khandual@xxxxxxx> 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@xxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm.h | 2 +- mm/page_alloc.c | 10 +++++----- 2 files changed, 6 insertions(+), 6 deletions(-) --- 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 }; _
