Date: Thu, 21 Dec 2017 13:35:27 +0100
From: LABBE Corentin <clabbe@baylibre.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: davem@davemloft.net, nhorman@tuxdriver.com,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC 1/3] crypto: Prevent to register duplicate
 cra_driver_name
Message-ID: <20171221123527.GA17586@Red>
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 <20171221063522.GA18211@gondor.apana.org.au>
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On Thu, Dec 21, 2017 at 05:35:22PM +1100, Herbert Xu wrote:
> On Wed, Dec 20, 2017 at 08:09:25PM +0000, Corentin Labbe wrote:
> > Each crypto algorithm "cra_name" can have multiple implementation called
> > "cra_driver_name".
> > If two different implementation have the same cra_driver_name, nothing
> > can easily differentiate them.
> > Furthermore the mechanism for getting a crypto algorithm with its
> > implementation name (crypto_alg_match() in crypto/crypto_user.c) will
> > get only the first one found.
> > 
> > So this patch prevent the registration of two implementation with the
> > same cra_driver_name.
> > 
> > Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
> 
> No this is intentional.  The idea is that you can hot-replace
> an implementation by registering a new version of it while the
> old one is still in use.  The new one will be used for all new
> allocations.
> 

But the new implementation is different from the first so should have a new name.
The only case I found is ctr-aes-ce, and both are different (use/dontuse simd) so qualifying for different name.

Anyway, any advice on how to populate properly /sys/crypto with unique name ?
I have two idea:
- A number which increment after each register
- cra_driver_name-priority

Or does I use /sys/crypto/cra_driver_name/priority ? (which need to use some usage count on cra_driver_name node)

Regards