[dpdk-dev] DPDK techboard minutes of September 15]

Pavan Nikhilesh Bhagavatula pbhagavatula at caviumnetworks.com
Wed Oct 4 11:15:46 CEST 2017

On Wed, Sep 20, 2017 at 09:36:48PM +0000, Ananyev, Konstantin wrote:

Hi everyone,

As per the last techboard meeting's conclusion,

> 3) Request for feedback regarding the new license requirement for the optimized version of 64bit division code from libdivide.
> It was pointed out that current 32-bit version is not BSD-licensed either:
> http://dpdk.org/browse/dpdk/tree/lib/librte_sched/rte_reciprocal.h
> TB recommendations:
> a) request LF legals to audit current lib/librte_sched/rte_reciprocal.h
> b) ask author of the patch for 64-bit version to:
>     - try to find BSD licensed implementation of the same algorithm
>     - contact the authors of the original code and ask their permission for re-licensing in BSD

I have contacted the author and got the following response

"libdivide is made available under the zlib license, which is very permissive
and compatible with BSD licenses. libdivide may be freely used in BSD-licensed
software, or also GPL or commercial software.

You do not have to add any copyright notices if you use libdivide in your
binaries. If you simply add libdivide.h to your sources and use it, you are
complying with the license.

It is my hope with libdivide that anyone can use it for anything.
The license is only so that nobody else claims to be the original author."

"It’s fine to modify libdivide to remove pieces you don’t use, or just copy
and paste the parts you do use. However it’s not reasonable to ask me to
contribute libdivide "without the licensing part;” in fact I cannot do so
because libdivide has more than one contributor.

The good news is that using libdivide under its license is very easy!
You only have to include the 14 line license text (under "ZLib license”).
The simplest way is with a source code comment in the file itself - I see you
have several other acknowledgements in rte_reciprocal.h, so that seems like a
natural place. A separate acknowledgements file is also fine if you prefer.

I hope that explains things and thanks for understanding,

The authors concern is contributing it to BSD licence will be a weak link
to the original author credits.

> Thanks,
> Konstantin


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