From: LABBE Corentin Subject: Re: [PATCH RFC 1/3] crypto: Prevent to register duplicate cra_driver_name Date: Thu, 21 Dec 2017 21:05:20 +0100 Message-ID: <20171221200520.GB954@Red> References: <1513800567-12764-1-git-send-email-clabbe@baylibre.com> <1513800567-12764-2-git-send-email-clabbe@baylibre.com> <20171221063522.GA18211@gondor.apana.org.au> <20171221123527.GA17586@Red> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, nhorman@tuxdriver.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org To: Herbert Xu Return-path: Content-Disposition: inline In-Reply-To: <20171221123527.GA17586@Red> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On Thu, Dec 21, 2017 at 01:35:27PM +0100, LABBE Corentin wrote: > 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 > > > > 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) I just see that kobject already have reference counting so this solution is the better. Regards