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Date:   Tue, 8 Mar 2022 20:57:04 -0800
From:   Eric Biggers <ebiggers@kernel.org>
To:     Keith Busch <kbusch@kernel.org>
Cc:     Vasily Gorbik <gor@linux.ibm.com>, linux-nvme@lists.infradead.org,
        linux-block@vger.kernel.org, linux-crypto@vger.kernel.org,
        linux-kernel@vger.kernel.org, axboe@kernel.dk, hch@lst.de,
        martin.petersen@oracle.com
Subject: Re: [PATCHv4 6/8] crypto: add rocksoft 64b crc guard tag framework
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On Tue, Mar 08, 2022 at 12:27:47PM -0800, Keith Busch wrote:
> On Tue, Mar 08, 2022 at 09:21:41PM +0100, Vasily Gorbik wrote:
> > On Thu, Mar 03, 2022 at 12:13:10PM -0800, Keith Busch wrote:
> > > Hardware specific features may be able to calculate a crc64, so provide
> > > a framework for drivers to register their implementation. If nothing is
> > > registered, fallback to the generic table lookup implementation. The
> > > implementation is modeled after the crct10dif equivalent.
> > 
> > Hi Keith,
> > 
> > this is failing on big-endian systems. I get the following on s390:
> 
> Oh, I see the put_unaligned_le64() in chksum_final() was not the correct
> action. I'll send an update, thank you for the report.

Or you could make the digests in your test vectors have have a consistent byte
order, probably little endian.  That's how "shash" algorithms in the crypto API
normally work, including crc32 and crc32c; they produce bytes as output.  I see
that crct10dif violates that convention, and I assume you copied it from there.
I'm not sure you should do that; crct10dif might be more of a one-off quirk.

- Eric