Re: [PATCH 07/10] crypto: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN

[Herbert Xu]

On Fri, Apr 15, 2022 at 10:05:21AM +0200, Ard Biesheuvel wrote:
>
> I guess that should be fixable. GIven that this is about padding
> rather than alignment, we could do something like
> 
> struct crypto_request {
>   union {
>       struct {
>         ... fields ...
>       };
>       u8 __padding[ARCH_DMA_MINALIGN];
>    };
>     void __ctx[]  __align(CRYPTO_MINALIGN);
> };
> 
> And then hopefully, we can get rid of the padding once we fix drivers
> doing non-cache coherent inbound DMA into those structures.

Sorry, I don't think this works.  kmalloc can still return something
that's not ARCH_DMA_MINALIGN-aligned, and therefore __ctx won't be
aligned correctly.

Cheers,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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