[Qemu-devel] [PATCH 0/7] virtio-blk: use alias properties in transport devices

[Stefan Hajnoczi <stefanha@redhat.com>]

Thanks for the feedback on the RFC.  This time around the alias property is
implemented at the QOM property level instead of at the qdev property level.

The virtio transport/device split is broken as follows:

1. The virtio-blk device is never finalized because the transport devices
   (virtio-blk-pci and friends) leak the refcount.

2. If we fix the refcount leak then we double-free the 'serial' string property
   upon hot unplug since its char* is copied into the virtio-blk device which
   has an identical 'serial' qdev property.

This series solves both of these problems as follows:

1. Introduce a QOM alias property that lets the transport device forward
   property accesses into the virtio device (the child).

2. Use alias properties in transport devices, instead of keeping a duplicate
   copy of the VirtIOBlkConf struct.

3. Fix the virtio-blk device refcount leak.  It's now safe to do this since the
   double-free has been resolved.

Stefan Hajnoczi (7):
  qom: add object_property_add_alias()
  virtio-blk: avoid qdev property definition duplication
  virtio-blk: move x-data-plane qdev property to virtio-blk.h
  virtio-blk: use aliases instead of duplicate qdev properties
  virtio-blk: drop virtio_blk_set_conf()
  virtio: fix virtio-blk child refcount in transports
  virtio-blk: move qdev properties into virtio-blk.c

 hw/block/virtio-blk.c          | 42 ++++++++++++++++++++++++++++------
 hw/s390x/s390-virtio-bus.c     | 10 ++------
 hw/s390x/s390-virtio-bus.h     |  1 -
 hw/s390x/virtio-ccw.c          |  7 ++----
 hw/s390x/virtio-ccw.h          |  1 -
 hw/virtio/virtio-pci.c         |  7 ++----
 hw/virtio/virtio-pci.h         |  1 -
 include/hw/virtio/virtio-blk.h | 19 +--------------
 include/qom/object.h           | 18 +++++++++++++++
 qom/object.c                   | 52 ++++++++++++++++++++++++++++++++++++++++++
 10 files changed, 112 insertions(+), 46 deletions(-)

-- 
1.9.0