The only difference is that theoretically some addrlabel rtnetlink
ops are not available if registration fails, but thats not really worse
than before as this used to panic() instead :-)
I can send a followup patch, to convert all of ipv6, should be easy
to propagate errors from addrlabel initialisation to its callsite.
Yes, please make ipv6 consistent in this area when you get a chance.
Thanks.