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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.

Anshuman Khandual committed 6 years ago

Commit ae70edd1 parent aa092592 files · +6 −6Browse files

Unified · Split

2 files
  1. include/linux/mm.h +1 −1
  2. mm/page_alloc.c +5 −5
include/linux/mm.h+1−1
@@ -867,7 +867,7 @@ enum compound_dtor_id { · 866 unmodified lines
867867 #endif
868868 NR_COMPOUND_DTORS,
869869 };
870−extern compound_page_dtor * const compound_page_dtors[];
870+extern compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS];
871871
872872 static inline void set_compound_page_dtor(struct page *page,
873873 enum compound_dtor_id compound_dtor)
mm/page_alloc.c+5−5
@@ -302,14 +302,14 @@ const char * const migratetype_names[MIGRATE_TYPES] = { · 301 unmodified lines
302302 #endif
303303 };
304304
305−compound_page_dtor * const compound_page_dtors[] = {
306− NULL,
307− free_compound_page,
305+compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
306+ [NULL_COMPOUND_DTOR] = NULL,
307+ [COMPOUND_PAGE_DTOR] = free_compound_page,
308308 #ifdef CONFIG_HUGETLB_PAGE
309− free_huge_page,
309+ [HUGETLB_PAGE_DTOR] = free_huge_page,
310310 #endif
311311 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
312− free_transhuge_page,
312+ [TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
313313 #endif
314314 };
315315