Re: [PATCH 09/11] crypto: remove LZO fallback from crypto 842

From: Herbert Xu
Date: Wed Apr 08 2015 - 10:39:18 EST

On Wed, Apr 08, 2015 at 10:28:23AM -0400, Dan Streetman wrote:
> So, the sw implementation is only for decompression; there's no sw
> compression implementation in these patches.

As a general rule we don't add any hardware implementation unless
there is a software implementation. The reason is that every new
algorithm creates an API (potentially a user-space API if the
algorithm can be exported via algif). But sometimes things slip

So I'm not going to immediately remove 842 but it would be nice
if we had a reference implementation so that if ever there were
another hardware 842 implmentation added then at least we have
something that we can judge against.

> The hw 842 driver is currently at drivers/crypto/nx, and the
> crypto/842 driver just calls the hw driver (after correctly
> aligning/sizing the provided buffers to what the hw driver expects),
> and falls back to the sw decompression if the hw decompression fails
> (there is no compression fallback, a failure is reported to the
> caller).
> Is that setup ok? If users had to directly call the hw driver,
> instead of using the generic crypto_comp interface, it would
> complicate things, e.g. in zswap it only expects to call
> crypto_comp_compress()/decompress(), not call the 842 hw driver
> directly.

I think the only thing that needs to happen for now is moving
crypto/842.c over to drivers/crypto/nx (perhaps merge it into
nx-842.c) so that it's obvious that this is not a generic

Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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