A link property can be set during creation, with
object_property_add_link() and later with object_property_set_link().

add_link() doesn't add a reference to the target object, while
set_link() does.

Furthemore, OBJ_PROP_LINK_UNREF_ON_RELEASE flags, set during add_link,
says whether a reference must be released when the property is destroyed.
This can lead to leaks if the property was later set_link(), as the
added reference is never released.

Instead, rename OBJ_PROP_LINK_UNREF_ON_RELEASE to OBJ_PROP_LINK_STRONG
and use that has an indication on how the link handle reference
management in set_link().
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20180531195119.22021-3-marcandre.lureau@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

The CanBusState state structure is created for each
emulated CAN channel. Individual clients/emulated
CAN interfaces or host interface connection registers
to the bus by CanBusClientState structure.

The CAN core is prepared to support connection to the
real host CAN bus network. The commit with such support
for Linux SocketCAN follows.

Implementation is as simple as possible.  There is no state to be
migrated, and messages prioritization and queuing are not considered
for now.  But it is intended to be extended when need arises.

Development repository and more documentation at

https://gitlab.fel.cvut.cz/canbus/qemu-canbus

The work is based on Jin Yang GSoC 2013 work funded
by Google and mentored in frame of RTEMS project GSoC
slot donated to QEMU.

Rewritten for QEMU-2.0+ versions and architecture cleanup
by Pavel Pisa (Czech Technical University in Prague).
Signed-off-by: NPavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>