Problem with error paths in various functions calling kvm_io_bus_unregister_dev

Our we to just assume
that calls to kvm_io_bug_unregister_dev always succeed as I disagree due to it allocating memory in kernel space that can easily fail. In additon I was wondering how the maintainers would like me to handle these calls as it's difficult due to it already being in error paths. Further more below is a link to the files and how the calls to kvm_io_bus_register_dev are executed in the respective error paths.
http://lxr.free-electrons.com/ident?i=kvm_io_bus_unregister_dev