Re: [PATCH v5 4/4] crypto: Add Allwinner Security System crypto accelerator

Herbert Xu
2014-10-31T08:18:48Z

On Fri, Oct 31, 2014 at 09:13:23AM +0100, Maxime Ripard wrote:
>
> I don't understand here. Why would other drivers *not* being affected?
>
> If the scatter list passed by AF_ALG can be in highmem, I guess it's
> the case for every driver out there. Almost every kernel code I've
> seen so far makes the assumption that the memory it has is mapped and
> accessible.
>
> Somehow, it's the driver's fault now, and not the part of kernel that
> actually does the allocation?

If you are implementing a crypto driver that is meant to handle
requests from the crypto API then yes you need to handle highmem.

As I said if enough drivers are unable to address highmem and
require copying/software fallbacks then we could provide this
through the API and the driver would then only need to declare
its lack of highmem support or use a helper.

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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