On Fri, 30 May 2014 13:17:41 +0200 Stefan Hajnoczi <stefa...@redhat.com> wrote:
> v3: > * Split qdev_alias_all_properties() into its own patch [Peter Crosthwaite] > * Do not dereference DEVICE_CLASS(class) inline [Peter Crosthwaite] > > v2: > * Add qdev_alias_all_properties() instead of virtio-blk-specific function > [Paolo] > * Explain refcount handling in doc comment [Paolo] > * Fix "property" duplicate typo [Peter Crosthwaite] > * Add "the same object or" to clarify commit description [Igor] > > 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. > > Note that this series only addresses virtio-blk. In later series we can > convert virtio net, scsi, rng, and serial. > > 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. > > Tested that hotplug/hotunplug of virtio-blk-pci still works. FWIW: I gave your qom-alias-property branch a quick test on s390. virtio-ccw: seems to work fine, hotunplug of virtio-blk-ccw is still fine, and the virtio-blk memory leaks due to missing finalization that valgind complained about are gone. s390-virtio: still boots, but with x-data-plane=on we get the predictable segfault in virtio_blk_data_plane_start() since s390-virtio doesn't do notifiers. Maybe the dataplane code should do a quick check for existence of the notifier callback when it allocates the dataplane structure? > > Stefan Hajnoczi (8): > 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 > qdev: add qdev_alias_all_properties() > 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 | 18 +++++++++------ > hw/core/qdev.c | 21 +++++++++++++++++ > 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/qdev-properties.h | 2 ++ > include/hw/virtio/virtio-blk.h | 19 --------------- > include/qom/object.h | 20 ++++++++++++++++ > qom/object.c | 52 > ++++++++++++++++++++++++++++++++++++++++++ > 12 files changed, 112 insertions(+), 47 deletions(-) >
