Merge branch 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

Merge branch 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-64, rwsem: Avoid store forwarding hazard in __downgrade_write
  x86-64, rwsem: 64-bit xadd rwsem implementation
  x86: Fix breakage of UML from the changes in the rwsem system
  x86-64: support native xadd rwsem implementation
  x86: clean up rwsem type system