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From:   Ben Finney <bignose@debian.org>
To:     Martin Steigerwald <Martin.Steigerwald@proact.de>
Cc:     Domenico Andreoli <cavok@debian.org>, 919356@bugs.debian.org,
        Kristian Fiskerstrand <k_f@gentoo.org>,
        Ben Finney <bignose@debian.org>,
        Nadia Yvette Chambers <nyc@holomorphy.com>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        "debian-legal\@lists.debian.org" <debian-legal@lists.debian.org>,
        "linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jens Axboe <jens.axboe@oracle.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: Re: Bug#919356: Licensing of include/linux/hash.h
In-Reply-To: <2977287.v5rPGuGa1n@merkaba> (Martin Steigerwald's message of
        "Mon, 11 Feb 2019 10:50:45 +0000")
References: <20190115170017.5gxarqxzfezgr5ld@dumbo>
        <c3aa1b37-60bb-aceb-10ba-9768157a2a5a@gentoo.org>
        <20190211072259.GA19224@nouveau>
        <20190115083241.6c6ftrw73xuv26j6@dumbo> <2977287.v5rPGuGa1n@merkaba>
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Date:   Tue, 12 Feb 2019 17:27:44 +1100
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Martin Steigerwald <Martin.Steigerwald@proact.de> writes:

> Well the file has in its header:
>
> /* Fast hashing routine for a long.
>    (C) 2002 William Lee Irwin III, IBM */
>
> /*
>  * Knuth recommends primes in approximately golden ratio to the maximum
>  * integer representable by a machine word for multiplicative hashing.
>  * Chuck Lever verified the effectiveness of this technique:
>  * http://www.citi.umich.edu/techreports/reports/citi-tr-00-1.pdf
>  *
>  * These primes are chosen to be bit-sparse, that is operations on
>  * them can use shifts and additions instead of multiplications for
>  * machines where multiplications are slow.
>  */
>
> It has been quite a while ago. I bet back then I did not regard this
> as license information since it does not specify a license. Thus I
> assumed it to be GPL-2 as the other files which have no license boiler
> plate. I.e.: Check file is it has different license, if not, then
> assume it has license as specified in COPYING.
>
> Not specifying a license can however also mean in this context that it
> has no license as the file contains copyright information from another
> author.

If a work (even one file) =E2=80=9Chas no license=E2=80=9D, that means no s=
pecial
permissions are granted and normal copyright applies: All rights
reserved, i.e. not redistributable. So, no license is grounds to
consider a work non-free and non-redistributable.

If, on the other hand, the file is to be free software, there would need
to be a clear grant of some free software license to that work.

Given the confusion over this file, I would consider it a significant
risk to just assume we have GPLv2 permissions without being told that
explicitly by the copyright holder. Rather, the reason we are seeking a
clearly-granted free license for this one file, is because we are trying
to replace a probably non-free file with the same code in it.

It seems we need to keep looking, and in the meantime assume we have no
free license in this file.

--=20
 \      =E2=80=9CIf the desire to kill and the opportunity to kill came alw=
ays |
  `\      together, who would escape hanging?=E2=80=9D =E2=80=94Mark Twain,=
 _Following |
_o__)                                                     the Equator_ |
Ben Finney <bignose@debian.org>