[ovs-dev] [next2 7/7] ofproto: Make rule construction and destruction more symmetric.

[Ethan Jackson]

> +/* Inserts 'rule' into 'cls'.  Until 'rule' is removed from 'cls', the caller
> + * must not modify or free it.
> + *
> + * 'cls' must not contain an identical rule (including wildcards, values of
> + * fixed fields, and priority).  Use classifier_find_rule_exactly() to find
> + * such a rule.
> + *
> + * Returns NULL if 'cls' does not contain a rule with an identical key, after
> + * inserting the new rule.  In this case, no rules are displaced by the new
> + * rule, even rules that cannot have any effect because the new rule matches a
> + * superset of their flows and has higher priority. */

This final paragraph bitrotted in the copy. classifier_insert()
doesn't return anything.

> +    classifier_remove(&ofproto->up.cls, &rule->up.cr);
>     LIST_FOR_EACH_SAFE (facet, next_facet, list_node, &rule->facets) {
>         facet_revalidate(ofproto, facet);
>     }
> -}
> -
> -static void
> -rule_remove(struct rule *rule_)
> -{
> -    struct rule_dpif *rule = rule_dpif_cast(rule_);
> -    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
> -
>     ofproto->need_revalidate = true;
> -    classifier_remove(&ofproto->up.cls, &rule->up.cr);
>  }

Why do we need to facet_revalidate each of 'rule''s facets given that
we set the ofproto->need_revalidate flag?  Are we worried that the
facet's will point to a destructed parent rule and cause problems?

Ethan