Re: [PATCH v4] crc32c: Implement CRC32c with slicing-by-8 algorithm

From: Darrick J. Wong
Date: Mon Oct 03 2011 - 20:55:34 EST

On Mon, Oct 03, 2011 at 09:35:13PM +0100, Herbert Xu wrote:
> On Mon, Oct 03, 2011 at 10:27:03PM +0200, Joakim Tjernlund wrote:
> >
> > > > Start from Bobs latest patches and add crc32c to lib/crc32.c
> > >
> > > If I did that, how should I handle patching in the hardware accelerated version
> > > on Intel systems? That switcheroo ability seems to have been Herbert Xu's
> > > motivation for moving crc32c into crypto/ in the first place:
> >
> > I don't know, I haven't looked at that problem. I suspect it moved because that
> > was the easiest solution. Having an identical impl. of crc32(only the table values differ)
> > in crypto compared to the one in lib is not the way forward though.
> You can always get crypto/crc32c.c to use call helpers from
> lib/crc32.c.

So what I think I'm hearing is...

1. Apply Bob's slice-by-8 algorithm patch to regular crc32.
2. Adapt crc32's build code to generate crc32c as well.
3. Remove crypto/crc32c.c's implementation and have it wrap the code generated
by #2.
4. Retain the current libcrc32c. I guess if you don't configure CRYPTO and
CRYPTO_CRC32C then it could also just reference the generated crc32c functions

Is this a satisfactory way to move forward?

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