Linux cryptographic layer development
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From: Herbert Xu <herbert@gondor.apana.org.au>
To: Catalin Vasile <cata.vasile@nxp.com>
Cc: "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
	"linux-crypto-owner@vger.kernel.org"
	<linux-crypto-owner@vger.kernel.org>,
	Horia Ioan Geanta Neag <horia.geanta@nxp.com>,
	Alexandru Porosanu <alexandru.porosanu@nxp.com>,
	Scott Wood <scott.wood@nxp.com>
Subject: Re: [PATCH] crypto: caam: add backlogging support
Date: Fri, 13 May 2016 21:50:13 +0800	[thread overview]
Message-ID: <20160513135013.GA16190@gondor.apana.org.au> (raw)
In-Reply-To: <DB5PR04MB1302B3363939FD8E0FD6BBB2EE740@DB5PR04MB1302.eurprd04.prod.outlook.com>

On Fri, May 13, 2016 at 12:55:09PM +0000, Catalin Vasile wrote:
> 
> We are inclining towards a hardware backlogging solution because on
> low end devices the software queue does not scale very well.
> Regarding your concerns, we are now evaluating adding a software queue based
> fallback solution: if the hardware backlogging fails because no hardware slots
> are available, backlog the job inside a crypto software queue.
> Is this hybrid configurable solution acceptable? Namely, if the hardware queue
> is full, to fallback to the crypto software queue.

It is but you need to be very careful so as to not introduce
reordering.

Essentially if you go to the fallback then you have to wait for
all the outstanding requests to complete before you complete the
fallback request.

A number of existing drivers that make use of fallbacks get this
wrong and we need to fix them.

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

      reply	other threads:[~2016-05-13 13:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-06 13:18 [PATCH] crypto: caam: add backlogging support Catalin Vasile
2016-05-06 13:18 ` [PATCH] crypto: caam: fix caam_jr_alloc() ret code Catalin Vasile
2016-05-10  9:54   ` Herbert Xu
2016-05-09 14:50 ` [PATCH] crypto: caam: add backlogging support Horia Ioan Geanta Neag
2016-05-10 14:59   ` Alexandru Porosanu
2016-05-10  9:46 ` Herbert Xu
2016-05-11  7:53   ` Catalin Vasile
2016-05-11 10:54     ` Herbert Xu
2016-05-13 12:55       ` Catalin Vasile
2016-05-13 13:50         ` Herbert Xu [this message]

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