From: Steffen Klassert <steffen.klassert@secunet.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ming Liu <ming.liu@windriver.com>, <davem@davemloft.net>,
<ying.xue@windriver.com>, <linux-crypto@vger.kernel.org>,
<netdev@vger.kernel.org>
Subject: Re: [PATCH] crypto: aesni-intel - avoid IPsec re-ordering
Date: Thu, 20 Nov 2014 08:26:51 +0100 [thread overview]
Message-ID: <20141120072650.GT6390@secunet.com> (raw)
In-Reply-To: <20141115031549.GA19208@gondor.apana.org.au>
On Sat, Nov 15, 2014 at 11:15:50AM +0800, Herbert Xu wrote:
> On Wed, Nov 12, 2014 at 09:41:38AM +0100, Steffen Klassert wrote:
> >
> > Everything below the local_bh_enable() should not run in atomic context
> > as the subsequent functions may set the CRYPTO_TFM_REQ_MAY_SLEEP flag.
>
> Actually I'm thinking of doing exactly that (disabling softirq in
> cryptd) to fix the reordering problem.
>
> Most threads do not use the FPU/SIMD so cryptd is only ever needed
> when we have a user-space app that touches the FPU/SIMD which then
> gets an interrupt to perform crypto in softirq. So forcing cryptd
> on everyone just because some apps touch the FPU/SIMD is a non-
> starter.
>
> The most straightforward solution is to always defer to cryptd once
> it gets started. This is bad because if a rarely used app that
> touches FPU/SIMD runs then we'll end up stuck in cryptd long after
> the app goes away.
>
> So what I'm thinking of is to have the softirq path forcibly regain
> control from cryptd where possible. This is tricky because cryptd
> might be in the middle of processing a request. So that's why I'd
> like to disable softirqs while we're processing a request.
>
What about to use a fallback algorithm that does not need to touch
FPU/SIMD in such cases? We would not need cryptd at all and it would
keep the requests in the right order because we don't defer them.
next prev parent reply other threads:[~2014-11-20 7:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-12 5:49 [PATCH] crypto: aesni-intel - avoid IPsec re-ordering Ming Liu
2014-11-12 8:41 ` Steffen Klassert
2014-11-12 8:51 ` Herbert Xu
2014-11-12 9:12 ` Steffen Klassert
2014-11-12 10:41 ` Ming Liu
2014-11-12 11:43 ` Steffen Klassert
2014-11-13 1:52 ` Ming Liu
2014-11-12 10:41 ` Ming Liu
2014-11-12 11:48 ` Steffen Klassert
2014-11-13 1:53 ` Ming Liu
2014-11-15 3:15 ` Herbert Xu
2014-11-20 7:26 ` Steffen Klassert [this message]
2014-11-20 7:43 ` Herbert Xu
2014-11-20 7:59 ` Steffen Klassert
2014-11-20 8:02 ` Herbert Xu
2015-01-06 1:05 ` Sunderam K
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