From: Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [PATCH v2 0/4] Introduce bulk mode for crypto engine framework
Date: Mon, 18 Apr 2016 16:17:53 +0800
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Cc: David Miller <davem@davemloft.net>,
	Alasdair G Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@redhat.com>, Jens Axboe <axboe@fb.com>,
	dm-devel@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
	david.s.gordon@intel.com, Tom Lendacky <thomas.lendacky@amd.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	smueller@chronox.de, tadeusz.struk@intel.com,
	Masanari Iida <standby24x7@gmail.com>, shli@kernel.org,
	Mark Brown <broonie@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-crypto@vger.kernel.org, linux-raid@vger.kernel.org
To: Baolin Wang <baolin.wang@linaro.org>
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On Mon, Apr 18, 2016 at 04:14:48PM +0800, Baolin Wang wrote:
> On 18 April 2016 at 16:04, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> > On Mon, Apr 18, 2016 at 03:58:59PM +0800, Baolin Wang wrote:
> >>
> >> That depends on the hardware engine. Some cipher hardware engines
> >> (like xts(aes) engine) can handle the intermediate values (IV) by
> >> themselves in one bulk block, which means we can increase the size of
> >> the request by merging request rather than always 512 bytes and thus
> >> increase the hardware engine processing speed. But for some other
> >> hardware engines (like cbc(aes) engine), they can not support bulk
> >> block, must sector by sector. So the engine drivers can select the
> >> suitable mode to do encryption/decryption.
> >
> > So what is this supposed to handle, xts or cbc?
> 
> As I know, now cbc engine also need to handle requests sector by
> sector, but for xts/ecb engine can support bulk block, which means can
> merge requests.

If it's just xts then why can't dm-crypt merge it and send a single
request?

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt