linux-kernel - Re: [BUGFIX 2/3] crypto: Remove CRYPTO_TFM_REQ_MAY_SLEEP flag in AES-NI accelerated ecb/cbc mode

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Date:	Thu, 18 Jun 2009 19:40:33 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Huang Ying <ying.huang@...el.com>
Cc:	linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org
Subject: Re: [BUGFIX 2/3] crypto: Remove CRYPTO_TFM_REQ_MAY_SLEEP flag in
	AES-NI accelerated ecb/cbc mode

On Mon, Jun 15, 2009 at 05:04:57PM +0800, Huang Ying wrote:
> Because AES-NI instructions will touch XMM state, corresponding code
> must be enclosed within kernel_fpu_begin/end, which used
> preempt_disable/enable. So sleep should be prevented between
> kernel_fpu_begin/end.
> 
> Signed-off-by: Huang Ying <ying.huang@...el.com>

I'll apply this for now.  But it would be much better to allow
sleeping in this case.

Couldn't we simply move the kernel_fpu_begin/end inside the loop?
It shouldn't be too expensive when it runs the 2nd time since it
doesn't have to save anything, right?

Cheer,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
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