[Qemu-devel] [PATCH v2 0/9] virtio: fix virtio child recount in transports

[arei.gonglei]

From: Gonglei <address@hidden>

virtio-$device-{pci, s390, ccw} all duplicate the
qdev properties of their virtio child. This approach does
not work well with string or pointer properties since we
must be careful about leaking or double-freeing them.

Use the QOM alias property to forward property accesses to the
VirtIORNG child.  This way no duplication is necessary.

For their child, object_initialize() leaves the object with a refcount of 1.
object_property_add_child() adds its own reference which is dropped
again when the property is deleted.

The upshot of this is that we always have a refcount >= 1.  Upon hot
unplug the virtio-$device child is not finalized!

Drop our reference after the child property has been added to the
parent.

The v1 as below:
 http://lists.gnu.org/archive/html/qemu-devel/2014-09/msg01208.html

Changes since v1:
 1. using alias properties avoid to double-free property.(Stefan)
 2. add handling all other virtio-devices had the same probleam.
 3. same handling for CCW and s390-virito.
 
Acknowledgements:
 I copied Stefan's commit message about virtio-blk which summarized
 reasons very well, I cannot agree more with him. Holp Stefan do not
 mind, thank you so much!

Gonglei (9):
  virtio-net: use aliases instead of duplicate qdev properties
  virtio: fix virtio-net child refcount in transports
  virtio/vhost scsi: use aliases instead of duplicate qdev properties
  virtio/vhost-scsi: fix virtio-scsi/vhost-scsi child refcount in
    transports
  virtio-serial: use aliases instead of duplicate qdev properties
  virtio-serial: fix virtio-serial child refcount in transports
  virtio-rng: use aliases instead of duplicate qdev properties
  virtio-rng: fix virtio-rng child refcount in transports
  virtio-balloon: fix virtio-balloon child refcount in transports

 hw/s390x/s390-virtio-bus.c | 16 ++++++++++------
 hw/s390x/virtio-ccw.c      | 18 +++++++++++-------
 hw/virtio/virtio-pci.c     | 18 +++++++++++-------
 3 files changed, 32 insertions(+), 20 deletions(-)

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1.7.12.4