[urcu.git] / lgpl-relicensing.md

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# Userspace-RCU LGPL 2.1+ re-licensing

Mathieu Desnoyers
May 13th, 2009

IBM Corporation allowed LGPLv2.1+ licensing of their contribution to the
userspace RCU library in a patch submitted on May 8, 2009 from Paul E.
McKenney and reviewed by Steven L. Bennett:

    https://lists.lttng.org/pipermail/lttng-dev/2009-May/012835.html

I (Mathieu Desnoyers) re-implemented ACCESS_ONCE(), likely(), unlikely() and
barrier() from scratch without reference to the original code.

    commit id : 2dc5fa0f7cfbfb0a64a7a67b39626650e863f16a

Bert Wesarg <bert.wesarg@googlemail.com> approved LGPL re-licensing of his
patch in an email dated May 13, 2009 :

    http://lkml.org/lkml/2009/5/13/16

xchg() primitives has been rewritten from a MIT-licensed cmpxchg for Intel
and powerpc. They are MIT-licensed and therefore usable in LGPL code.
This cmpxchg code was obtained from the atomic_ops project:

    http://www.hpl.hp.com/research/linux/atomic_ops/

I (Mathieu Desnoyers) wrote the remainder of the code.

The license for the library files in this project was therefore changed to
LGPLv2.1 on May 13, 2009, as detailed in LICENSE.
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	2	SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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	4	SPDX-License-Identifier: CC-BY-4.0
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	6
	7	# Userspace-RCU LGPL 2.1+ re-licensing
	8
	9	Mathieu Desnoyers
	10	May 13th, 2009
	11
	12	IBM Corporation allowed LGPLv2.1+ licensing of their contribution to the
	13	userspace RCU library in a patch submitted on May 8, 2009 from Paul E.
	14	McKenney and reviewed by Steven L. Bennett:
	15
	16	https://lists.lttng.org/pipermail/lttng-dev/2009-May/012835.html
	17
	18	I (Mathieu Desnoyers) re-implemented ACCESS_ONCE(), likely(), unlikely() and
	19	barrier() from scratch without reference to the original code.
	20
	21	commit id : 2dc5fa0f7cfbfb0a64a7a67b39626650e863f16a
	22
	23	Bert Wesarg <bert.wesarg@googlemail.com> approved LGPL re-licensing of his
	24	patch in an email dated May 13, 2009 :
	25
	26	http://lkml.org/lkml/2009/5/13/16
	27
	28	xchg() primitives has been rewritten from a MIT-licensed cmpxchg for Intel
	29	and powerpc. They are MIT-licensed and therefore usable in LGPL code.
	30	This cmpxchg code was obtained from the atomic_ops project:
	31
	32	http://www.hpl.hp.com/research/linux/atomic_ops/
	33
	34	I (Mathieu Desnoyers) wrote the remainder of the code.
	35
	36	The license for the library files in this project was therefore changed to
	37	LGPLv2.1 on May 13, 2009, as detailed in LICENSE.