linux-kernel - Re: [PATCH v9 00/20] simplify crypto wait for async op

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Date:   Tue, 17 Oct 2017 15:06:29 +0100
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Gilad Ben-Yossef <gilad@...yossef.com>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Jonathan Corbet <corbet@....net>,
        David Howells <dhowells@...hat.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Gary Hook <gary.hook@....com>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Arnaud Ebalard <arno@...isbad.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>, dm-devel@...hat.com,
        Steve French <sfrench@...ba.org>,
        "Theodore Y. Ts'o" <tytso@....edu>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Mimi Zohar <zohar@...ux.vnet.ibm.com>,
        Dmitry Kasatkin <dmitry.kasatkin@...il.com>,
        James Morris <james.l.morris@...cle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>, linux-cifs@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-ima-user@...ts.sourceforge.net,
        netdev@...r.kernel.org, samba-technical@...ts.samba.org,
        linux-kernel@...r.kernel.org, linux-fscrypt@...r.kernel.org,
        keyrings@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-crypto@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-ima-devel@...ts.sourceforge.net,
        linux-arm-kernel@...ts.infradead.org,
        Ofir Drang <ofir.drang@....com>
Subject: Re: [PATCH v9 00/20] simplify crypto wait for async op

On Sun, Oct 15, 2017 at 10:19:45AM +0100, Gilad Ben-Yossef wrote:
> Many users of kernel async. crypto services have a pattern of
> starting an async. crypto op and than using a completion
> to wait for it to end.
> 
> This patch set simplifies this common use case in two ways:
> 
> First, by separating the return codes of the case where a
> request is queued to a backlog due to the provider being
> busy (-EBUSY) from the case the request has failed due
> to the provider being busy and backlogging is not enabled
> (-EAGAIN).
> 
> Next, this change is than built on to create a generic API
> to wait for a async. crypto operation to complete.
> 
> The end result is a smaller code base and an API that is
> easier to use and more difficult to get wrong.
> 
> The patch set was boot tested on x86_64 and arm64 which
> at the very least tests the crypto users via testmgr and
> tcrypt but I do note that I do not have access to some
> of the HW whose drivers are modified nor do I claim I was
> able to test all of the corner cases.
> 
> The patch set is based upon linux-next release tagged
> next-20171013.

Has there been any performance impact analysis of these changes?  I
ended up with patches for one of the crypto drivers which converted
its interrupt handling to threaded interrupts being reverted because
it caused a performance degredation.

Moving code to latest APIs to simplify it is not always beneficial.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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