Merge remote-tracking branch 'stefanha/block' into staging

# By Kevin Wolf (4) and others
# Via Stefan Hajnoczi
* stefanha/block:
  dataplane: support viostor virtio-pci status bit setting
  dataplane: avoid reentrancy during virtio_blk_data_plane_stop()
  win32-aio: use iov utility functions instead of open-coding them
  win32-aio: Fix memory leak
  win32-aio: Fix vectored reads
  aio: Fix return value of aio_poll()
  ide: Remove wrong assertion
  block: fix null-pointer bug on error case in block commit