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

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

Pull UML updates from Richard Weinberger:
 "This pile contains mostly fixes and improvements for issues identified
  by Richard W M Jones while adding UML as backend to libguestfs"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Add irq chip um/mask handlers
  um: prctl: Do not include linux/ptrace.h
  um: Run UML in it's own session.
  um: Cleanup SIGTERM handling
  um: ubd: Introduce submit_request()
  um: ubd: Add REQ_FLUSH suppport
  um: Implement probe_kernel_read()
  um: hostfs: Fix writeback