[dm-devel] [PATCH v2 0/2] Introduce the bulk IV mode for improving the crypto engine efficiency

[Milan Broz]

On 01/13/2016 12:38 AM, Arnd Bergmann wrote:
> On Tuesday 12 January 2016 18:31:19 Mikulas Patocka wrote:
>>
>> Another possibility is to use dm-crypt block size 4k and use a filesystem 
>> with 4k blocksize on it (it will never send requests not aligned on 4k 
>> boundary, so we could reject such requests with an error).
> 
> Is there ever a reason to use something other than 4K block size on
> dm-crypt?

Most existing sw FDE systems use 512bytes blocks. I would like to see
configurable block size (at least up to 4k) but as Mikulas pointed out
it opens several new problems. 

Anyway, I do not see reason why crypto accelerators should not process
these small sectors better - just hw must be designed for it.

Milan