Re: [PATCH] crypto: arm/aes-neonbs - process 8 blocks in parallel if we can

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 29 December 2016 at 02:23, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Wed, Dec 28, 2016 at 07:50:44PM +0000, Ard Biesheuvel wrote:
>>
>> So about this chunksize, is it ever expected to assume other values
>> than 1 (for stream ciphers) or the block size (for block ciphers)?
>> Having block size, IV size *and* chunk size fields may be confusing to
>> some already, so if the purpose of chunk size can be fulfilled by a
>> single 'stream cipher' flag, perhaps we should change that first.
>
> For users (such as algif) it's much more convenient to have a size
> rather than a flag because that's what they need to determine the
> minimum size for partial updates.
>
> For implementors you don't need to specify the chunksize at all
> unless you're a stream cipher (or some other case in future where
> the minimum partial update size is not equal to your block size).
>

OK, fair enough. So I will add a field 'walksize' to the skcipher_alg
struct in my proposal. I think the walk logic itself needs to change
very little, though: we can simply set the walk's chunksize to the
skcipher's walksize if it exceeds its chunksize (and walksize %
chunksize should be 0 in any case, and walksize should default to the
chunksize if not supplied)

If this sounds reasonable to you, I will hack something up next week.