From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook Move tag_clear_highpage() loops out of the kasan_has_integrated_init() clause as a code simplification. This patch does no functional changes. Link: https://lkml.kernel.org/r/587e3fc36358b88049320a89cc8dc6deaecb0cda.1643047180.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> Acked-by: Marco Elver <elver@xxxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Peter Collingbourne <pcc@xxxxxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) --- a/mm/page_alloc.c~kasan-page_alloc-combine-tag_clear_highpage-calls-in-post_alloc_hook +++ a/mm/page_alloc.c @@ -2367,30 +2367,30 @@ inline void post_alloc_hook(struct page * KASAN unpoisoning and memory initializion code must be * kept together to avoid discrepancies in behavior. */ + + /* + * If memory tags should be zeroed (which happens only when memory + * should be initialized as well). + */ + if (init_tags) { + int i; + + /* Initialize both memory and tags. */ + for (i = 0; i != 1 << order; ++i) + tag_clear_highpage(page + i); + + /* Note that memory is already initialized by the loop above. */ + init = false; + } if (kasan_has_integrated_init()) { if (gfp_flags & __GFP_SKIP_KASAN_POISON) SetPageSkipKASanPoison(page); - if (init_tags) { - int i; - - for (i = 0; i != 1 << order; ++i) - tag_clear_highpage(page + i); - } else { + if (!init_tags) kasan_unpoison_pages(page, order, init); - } } else { kasan_unpoison_pages(page, order, init); - if (init_tags) { - int i; - - for (i = 0; i < 1 << order; i++) - tag_clear_highpage(page + i); - - init = false; - } - if (init) kernel_init_free_pages(page, 1 << order); } _
