Re: [PATCH] cryptoloop

[Andrew Morton]

Jari Ruusu <[e-mail]> wrote:
>
> Changing transfer function prototype may be a tiny speed improvement for one
>  implementation that happens to use unoptimal API, but at same time be tiny
>  speed degration to other implementations that use more saner APIs. I am
>  unhappy with that change, because I happen to maintain four such transfers
>  that would be subject to tiny speed degration.

Both the source and dest pages are being mapped with a sleeping kmap() at
present.  This way we can stop doing that, which is a significant saving on
highmem and a more significant saving on SMP highmem. (crypto uses kmap_atomic).

Why is the loop driver taking a copy of all the pages btw?  Looks to me
that we can just clone the bio and save an entire copy?