[PATCH] x86: implement always-locked bit ops, for memory shared with an SMP hypervisor

Add "always lock'd" implementations of set_bit, clear_bit and change_bit and
the corresponding test_and_ functions.  Also add "always lock'd"
implementation of cmpxchg.  These give guaranteed strong synchronisation and
are required for non-SMP kernels running on an SMP hypervisor.

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>