linux-kernel - Re: [PATCH v5 4/4] crypto: Add Allwinner Security System crypto accelerator

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Message-ID: <20141103093446.GG11263@lukather>
Date:	Mon, 3 Nov 2014 10:34:46 +0100
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	Corentin LABBE <clabbe.montjoie@...il.com>, robh+dt@...nel.org,
	pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	linux@....linux.org.uk, davem@...emloft.net,
	grant.likely@...aro.org, akpm@...ux-foundation.org,
	gregkh@...uxfoundation.org, joe@...ches.com,
	mchehab@....samsung.com, crope@....fi, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-crypto@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v5 4/4] crypto: Add Allwinner Security System crypto
 accelerator

On Fri, Oct 31, 2014 at 06:05:22PM +0800, Herbert Xu wrote:
> On Fri, Oct 31, 2014 at 10:57:06AM +0100, Maxime Ripard wrote:
> >
> > On a 3.18-rc2 kernel:
> > 
> > $ git grep kmap -- crypto/
> > crypto/ahash.c:                         walk->data = kmap(walk->pg);
> > crypto/ahash.c:                         walk->data = kmap_atomic(walk->pg);
> > crypto/async_tx/async_memcpy.c:         dest_buf = kmap_atomic(dest) + dest_offset;
> > crypto/async_tx/async_memcpy.c:         src_buf = kmap_atomic(src) + src_offset;
> > crypto/scatterwalk.c:                   return kmap_atomic(scatterwalk_page(walk)) +
> > crypto/shash.c:                         data = kmap_atomic(sg_page(sg));
> > crypto/shash.c:                         data = kmap_atomic(sg_page(sg));
> > 
> > None of the drivers are.
> 
> What do you mean? It's precisely because the page can be in highmem
> that we are mapping it.  If it's not in highmem it'll be a noop.

What I mean is that since you are saying that drivers should do the
kmap themselves, then *all* of the drivers are broken if they are not
using it. And all of them are missing this kmap.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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