Re: [PATCH v2 04/10] crypto/compress: add asynchronous compression support

From: Li, Weigang
Date: Wed Jan 27 2016 - 02:59:18 EST

On 1/27/2016 3:41 PM, Herbert Xu wrote:
On Tue, Jan 26, 2016 at 05:15:06PM +0900, Joonsoo Kim wrote:
From: Weigang Li <>

Now, asynchronous compression APIs are supported. There is no asynchronous
compression driver now but this APIs can be used as front-end to
synchronous compression algorithm. In this case, scatterlist would be
linearlized when needed so it would cause some overhead.

Signed-off-by: Weigang Li <>
Signed-off-by: Joonsoo Kim <>

I think we should be able to use this for the synchronous case
too, like we do with skcipher and ahash.

The main difference that I can see right now is that acomp always
allocates a context through the request object while scomp does not.

This difference is entirely artificial as we could also make the
context conditional for acomp.

The reason we had the shash/ahash division is because the shash
interface offers a direct pointer interface while ahash is SG-based.
Otherwise ahash is just as able as shash to handle synchronous

At this point in time I don't see such a fundamental distinction
between acomp and scomp.


The acomp is also SG-based, while scomp only accepts flat buffer.