From mboxrd@z Thu Jan  1 00:00:00 1970
From: Leon Romanovsky <leonro@mellanox.com>
Subject: Re: [PATCH] Avoid that check_shl_overflow() triggers a compiler
 warning when building with W=1
Date: Thu, 7 Mar 2019 17:02:36 +0000
Message-ID: <20190307170230.GR1789@mtr-leonro.mtl.com>
References: <20190307010153.81157-1-bvanassche@acm.org>
 <20190307012417.GU1758@mellanox.com>
 <8a5bd9ae-ebfe-687c-2868-d0f2a610d1e0@acm.org>
 <20190307072428.GJ1789@mtr-leonro.mtl.com>
 <4d90c392-5b6a-fea0-e6cf-c49ac19fdf30@acm.org>
 <20190307154020.GN1789@mtr-leonro.mtl.com>
 <CAGXu5jLBPpKOT-NV1P0nuFeSQYfoNY_8B0V4gcQg18xHPUVbhQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1;
        protocol="application/pgp-signature"; boundary="Mit9XoPEfICDqq/V"
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <CAGXu5jLBPpKOT-NV1P0nuFeSQYfoNY_8B0V4gcQg18xHPUVbhQ@mail.gmail.com>
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
To: Kees Cook <keescook@chromium.org>
Cc: Bart Van Assche <bvanassche@acm.org>, Jason Gunthorpe <jgg@mellanox.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>, Rasmus Villemoes <linux@rasmusvillemoes.dk>
List-Id: linux-rdma@vger.kernel.org

--Mit9XoPEfICDqq/V
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Thu, Mar 07, 2019 at 08:52:51AM -0800, Kees Cook wrote:
> On Thu, Mar 7, 2019 at 7:40 AM Leon Romanovsky <leonro@mellanox.com> wrote:
> >
> > On Thu, Mar 07, 2019 at 06:53:54AM -0800, Bart Van Assche wrote:
> > > On 3/6/19 11:24 PM, Leon Romanovsky wrote:
> > > > My simple patch passes too :).
> > >
> > > Can you repost your patch?
> >
> > https://patchwork.kernel.org/patch/10841079/
> >
> > As Rasmus wrote, the thing is to avoid a < 0 check. In my patch,
> > I converted a <= 0 to !(a > 0 || a == 0) expression.
>
> I'd be happy either way. Is there a larger benefit to having a safe
> "is_non_negative()" helper, or should we go with the minimal change to
> the shl macro?

I personally prefer simplest possible solution.

>
> -Kees
>
> --
> Kees Cook

--Mit9XoPEfICDqq/V
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=NFtk
-----END PGP SIGNATURE-----

--Mit9XoPEfICDqq/V--