Re: [PATCH 09/22] dm-crypt: Make use of the new sg_map helper in 4 call sites

From	Logan Gunthorpe <logang@deltatee.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 09/22] dm-crypt: Make use of the new sg_map helper in 4 call sites
Date	2017-04-14 18:10 +0200
Message-ID	<twbXj-3bL-3@gated-at.bofh.it> (permalink)
References	<tvV69-P8-5@gated-at.bofh.it> <tvV69-P8-3@gated-at.bofh.it> <tw4VP-7gB-1@gated-at.bofh.it>
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On 14/04/17 02:39 AM, Christoph Hellwig wrote:
> On Thu, Apr 13, 2017 at 04:05:22PM -0600, Logan Gunthorpe wrote:
>> Very straightforward conversion to the new function in all four spots.
> 
> I think the right fix here is to switch dm-crypt to the ahash API
> that takes a scatterlist.

Hmm, well I'm not sure I understand the code enough to make that
conversion. But I was looking at it. One tricky bit seems to be that
crypt_iv_lmk_one adds a seed, skips the first 16 bytes in the page and
then hashes another 16 bytes from other data. What would you do
construct a new sgl for it and pass it to the ahash api?

The other thing is crypt_iv_lmk_post also seems to modify the page after
the hash with a  crypto_xor so you'd still need at least one kmap in there.

Logan

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[PATCH 09/22] dm-crypt: Make use of the new sg_map helper in 4 call sites Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:10 +0200
  Re: [PATCH 09/22] dm-crypt: Make use of the new sg_map helper in 4         call sites Christoph Hellwig <hch@lst.de> - 2017-04-14 10:40 +0200
    Re: [PATCH 09/22] dm-crypt: Make use of the new sg_map helper in 4  call sites Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 18:10 +0200

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