Re: [libvirt] [PATCH 6/6] conf: Clean up object referencing for Add and Remove

When adding a new object to the domain object list, there should have been 2 virObjectRef calls made one for each list into which the object was placed to match the 2 virObjectUnref calls that would occur during Remove as part of virHashRemoveEntry when virObjectFreeHashData is called when the element is removed from the hash table as set up in virDomainObjListNew. Some drivers (libxl, lxc, qemu, and vz) handled this inconsistency by calling virObjectRef upon successful return from virDomainObjListAdd in order to use virDomainObjEndAPI when done with the returned @vm. While others (bhyve, openvz, test, and vmware) handled this via only calling virObjectUnlock upon successful return from virDomainObjListAdd. This patch will "unify" the approach to use virDomainObjEndAPI for any @vm successfully returned from virDomainObjListAdd. Because list removal is so tightly coupled with list addition, this patch fixes the list removal algorithm to return the object as entered - "locked and reffed". This way, the callers can then decide how to uniformly handle add/remove success and failure. This removes the onus on the caller to "specially handle" the @vm during removal processing. The Add/Remove logic allows for some logic simplification such as in libxl where we can Remove the @vm directly rather than needing to set a @remove_dom boolean and removing after the libxlDomainObjEndJob completes as the @vm is locked/reffed. Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; ---

@@ -386,8 +386,7 @@ virDomainObjListRemoveLocked(virDomainObjListPtr doms, * no one else is either waiting for 'dom' or still using it. * * When this function returns, @dom will be removed from the hash - * tables, unlocked, and returned with the refcnt that was present - * upon entry. + * tables and returned with lock and refcnt that was present upon entry.