Merge branch 'stable/for-linus-3.3' into linux-next

Merge branch 'stable/for-linus-3.3' into linux-next

* stable/for-linus-3.3:
  xen/xenbus-frontend: Make error message more clear
  xen/privcmd: Remove unused support for arch specific privcmp mmap
  xen: Add xenbus_backend device
  xen: Add xenbus device driver
  xen: Add privcmd device driver
  xen/gntalloc: fix reference counts on multi-page mappings
  xen/gntalloc: release grant references on page free
  xen/events: prevent calling evtchn_get on invalid channels
  xen/granttable: Support transitive grants
  xen/granttable: Support sub-page grants
  xen/granttable: Improve comments for function pointers