From: Yu Zhao <yuzhao@xxxxxxxxxx> Subject: mm/slub.c: clean up validate_slab() The function doesn't need to return any value, and the check can be done in one pass. There is a behavior change: before the patch, we stop at the first invalid free object; after the patch, we stop at the first invalid object, free or in use. This shouldn't matter because the original behavior isn't intended anyway. Link: http://lkml.kernel.org/r/20191108193958.205102-1-yuzhao@xxxxxxxxxx Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Cc: Yu Zhao <yuzhao@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) --- a/mm/slub.c~mm-clean-up-validate_slab +++ a/mm/slub.c @@ -4384,31 +4384,26 @@ static int count_total(struct page *page #endif #ifdef CONFIG_SLUB_DEBUG -static int validate_slab(struct kmem_cache *s, struct page *page, +static void validate_slab(struct kmem_cache *s, struct page *page, unsigned long *map) { void *p; void *addr = page_address(page); - if (!check_slab(s, page) || - !on_freelist(s, page, NULL)) - return 0; + if (!check_slab(s, page) || !on_freelist(s, page, NULL)) + return; /* Now we know that a valid freelist exists */ bitmap_zero(map, page->objects); get_map(s, page, map); for_each_object(p, s, addr, page->objects) { - if (test_bit(slab_index(p, s, addr), map)) - if (!check_object(s, page, p, SLUB_RED_INACTIVE)) - return 0; - } + u8 val = test_bit(slab_index(p, s, addr), map) ? + SLUB_RED_INACTIVE : SLUB_RED_ACTIVE; - for_each_object(p, s, addr, page->objects) - if (!test_bit(slab_index(p, s, addr), map)) - if (!check_object(s, page, p, SLUB_RED_ACTIVE)) - return 0; - return 1; + if (!check_object(s, page, p, val)) + break; + } } static void validate_slab_slab(struct kmem_cache *s, struct page *page, _
