Re: Bug#919356: Licensing of include/linux/hash.h

[Ben Finney <bignose@debian.org>]

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) “has no license”, that means no special
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.

-- 
 \      “If the desire to kill and the opportunity to kill came always |
  `\      together, who would escape hanging?” —Mark Twain, _Following |
_o__)                                                     the Equator_ |
Ben Finney <bignose@debian.org>