Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2;
MIME-Version: 1.0
References: <YpC1/rWeVgMoA5X1@gondor.apana.org.au> <Yui+kNeY+Qg4fKVl@gondor.apana.org.au>
 <Yzv0wXi4Uu2WND37@gondor.apana.org.au> <Y5mGGrBJaDL6mnQJ@gondor.apana.org.au>
 <Y/MDmL02XYfSz8XX@gondor.apana.org.au> <ZEYLC6QsKnqlEQzW@gondor.apana.org.au>
 <ZJ0RSuWLwzikFr9r@gondor.apana.org.au> <ZOxnTFhchkTvKpZV@gondor.apana.org.au>
 <ZUNIBcBJ0VeZRmT9@gondor.apana.org.au> <CAHk-=wj0-QNH5gMeYs3b+LU-isJyE4Eu9p8vVH9fb-vHHmUw0g@mail.gmail.com>
 <ZUSKk6Tb7+0n9X5s@gondor.apana.org.au>
In-Reply-To: <ZUSKk6Tb7+0n9X5s@gondor.apana.org.au>
From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 2 Nov 2023 20:32:36 -1000
Message-ID: <CAHk-=wh=xH7TNHeaYdsrVW6p1fCQEV5PZMpaFNsZyXYqzn8Stg@mail.gmail.com>
Subject: Re: [GIT PULL] Crypto Update for 6.7
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Steffen Klassert <steffen.klassert@secunet.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, 2 Nov 2023 at 19:52, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> Fair enough.  How about adding an EXPERT dependency on this?

I think that would help the situation, but I assume the sizing for the
jitter buffer is at least partly due to trying to account for cache
sizing or similar issues?

Which really means that I assume any static compile-time answer to
that question is always wrong - whether you are an expert or not.
Unless you are just building the thing for one particular machine.

So I do think the problem is deeper than "this is a question only for
experts". I definitely don't think you should ask a regular user (or
even a distro kernel package manager). I suspect it's likely that the
question is just wrong in general - because any particular one buffer
size for any number of machines simply cannot be the right answer.

I realize that the commit says "*allow* for configuration of memory
size", but I really question the whole approach.

But yes - hiding these questions from any reasonable normal user is at
least a good first step.

              Linus