This patch reverts parts of commits 0d8b24f6b and 0785966d dealing with
the addition of a controller during virDomainHostdevAssignAddress. This
caused a regression for the hostdev hotplug path which assumes the
qemuDomainFindOrCreateSCSIDiskController will add the new controller
during qemuDomainAttachHostSCSIDevice to both the running domain and
the domain def controller list when the controller doesn't yet exist
(whether due to no SCSI controllers existing or the addition of a new
controller because existing ones are full).
Since commit id 0d8b24f6 will call virDomainHostdevAssignAddress during
virDomainDeviceDefPostParseInternal which is called either during domain
definition post processing (via an iterator during virDomainDefPostParse)
or directly from virDomainDeviceDefParse during hotplug, the change
broke the "side effect" of being able to add both a hostdev and controller
to the running domain.
The regression would only be seen if the running domain didn't have a
SCSI controller already defined or if the existing SCSI controller was
"full" of devices and a new controller needed to be created.
This patch will also add some extra comments to the code to avoid a
similar future change.
Signed-off-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
dc692438f3