Re: [PATCH v3] devres: Explicitly align datai[] to 64-bit

From: Peter Zijlstra
Date: Mon Jul 09 2018 - 10:07:47 EST


On Mon, Jul 09, 2018 at 04:45:50PM +0300, Alexey Brodkin wrote:
> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -24,8 +24,12 @@ struct devres_node {
>
> struct devres {
> struct devres_node node;
> - /* -- 3 pointers */
> - unsigned long long data[]; /* guarantee ull alignment */
> + /*
> + * data[] must be 64 bit aligned even on 32 bit architectures
> + * because it might be accessed by instructions that require
> + * aligned memory arguments such as atomic64_t.
> + */
> + u8 __aligned(8) data[];
> };

Seeing that this ends up in a semi generic allocation thing, I don't
feel this should be different from ARCH_KMALLOC_MINALIGN.