Moving Userspace RCU (urcu) from GPL to LGPL license

[Mathieu Desnoyers <compudj@krystal.dyndns.org>]

Hi Paul,

I think that it would be good to distribute the userspace rcu work we
are currently doing (ref. :
http://lttng.org/cgi-bin/gitweb.cgi?p=userspace-rcu.git) as a
LGPL library rather than GPL so it can be linked to the userspace part
of the LTTng tracer. We want to provide this tracer as a LGPL library so
proprietary applications can link to it and therefore be traceable. The
only thing is that we cannot put GPL code into a LGPL library.

The other point is that I use a few low-level primitives from the Linux
kernel header (e.g. atomic increment for x86, barrier macros). Those are
simple one-liners, but, still, I wonder about the licensing
implications. I could simply "rewrite" them, but that would be a shame
to have a different primitive implementation of those simple primitives
in userspace and in kernel-space just for a licensing question. I would
really like to keep the Linux kernel coding-style within this library.
So the question would be : are those headers, distributed with the Linux
kernel, distributed under GPL license ? Is there any special clause that
would permit using their content under LGPL ? If not, would the
community see such use favorably ?

Ideas/comments are welcome.

Thanks,

Mathieu


-- 
Mathieu Desnoyers
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