Re: [PATCH v3 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning

[Vincenzo Frascino <vincenzo.frascino@arm.com>]

On 03/01/2019 18:45, Andrey Konovalov wrote:
> Instead of changing cache->align to be aligned to KASAN_SHADOW_SCALE_SIZE
> in kasan_cache_create() we can reuse the ARCH_SLAB_MINALIGN macro.
> 
> Suggested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---
>  arch/arm64/include/asm/cache.h | 6 ++++++
>  mm/kasan/common.c              | 2 --
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
> index 13dd42c3ad4e..eb43e09c1980 100644
> --- a/arch/arm64/include/asm/cache.h
> +++ b/arch/arm64/include/asm/cache.h
> @@ -58,6 +58,12 @@
>   */
>  #define ARCH_DMA_MINALIGN	(128)
>  
> +#ifdef CONFIG_KASAN_SW_TAGS
> +#define ARCH_SLAB_MINALIGN	(1ULL << KASAN_SHADOW_SCALE_SHIFT)
> +#else
> +#define ARCH_SLAB_MINALIGN	__alignof__(unsigned long long)
> +#endif
> +

Could you please remove the "#else" case here, because it is redundant (it is
defined in linux/slab.h as ifndef) and could be misleading in future?

>  #ifndef __ASSEMBLY__
>  
>  #include <linux/bitops.h>
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 03d5d1374ca7..44390392d4c9 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -298,8 +298,6 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
>  		return;
>  	}
>  
> -	cache->align = round_up(cache->align, KASAN_SHADOW_SCALE_SIZE);
> -
>  	*flags |= SLAB_KASAN;
>  }
>  
> 

-- 
Regards,
Vincenzo