From: =?UTF-8?B?SG9yaWEgR2VhbnTEgw==?= <horia.geanta@freescale.com>
Subject: Re: [PATCH 2/4] net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating
 crypto request
Date: Sat, 14 Mar 2015 14:16:37 +0200
Message-ID: <550426A5.4090603@freescale.com>
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Cc: <linux-crypto@vger.kernel.org>, <netdev@vger.kernel.org>,
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To: David Miller <davem@davemloft.net>, <herbert@gondor.apana.org.au>
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On 3/13/2015 9:46 PM, David Miller wrote:
> From: Horia Geanta <horia.geanta@freescale.com>
> Date: Fri, 13 Mar 2015 19:15:22 +0200
> 
>> Some crypto backends might require the requests' private contexts
>> to be allocated in DMA-able memory.
>>
>> Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
> 
> No way.
> 
> Upper layers should be absolutely not required to know about such
> requirements.
> 
> Such details _must_ be hidden inside of the crypto layer and drivers
> and not leak out into the users of the crypto interfaces.

If you look at patch 1/4:
http://www.mail-archive.com/linux-crypto@vger.kernel.org/msg13428.html
that's what's done for {aead,ablkcipher,ahash}_request_alloc().

Thus users (upper layers) that allocate the crypto requests using the
crypto API are unaware of the requirement.

However, ESP is not using aead_request_alloc(). This breaks the
interface and thus some crypto implementation details are not transparent.