On Tue, Jul 24, 2018 at 3:30 PM Cong Wang <xiyou.wangc...@gmail.com> wrote:
>
> On Mon, Jul 23, 2018 at 12:25 AM Jiri Pirko <j...@resnulli.us> wrote:
> > + switch (n->nlmsg_type) {
> > + case RTM_NEWCHAIN:
> > + /* In case the chain was successfully added, take a
> > reference
> > + * to the chain. This ensures that an empty chain
> > + * does not disappear at the end of this function.
> > + */
> > + tcf_chain_hold(chain);
> > + chain->explicitly_created = true;
> > + tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
> > + RTM_NEWCHAIN, false);
> > + break;
> > + case RTM_DELCHAIN:
> > + /* Flush the chain first as the user requested chain
> > removal. */
> > + tcf_chain_flush(chain);
> > + /* In case the chain was successfully deleted, put a
> > reference
> > + * to the chain previously taken during addition.
> > + */
> > + tcf_chain_put_explicitly_created(chain);
> > + break;
>
> I don't see you send notification to user-space when deleting a chain,
> am I missing anything?
Oh, it is hidden in tcf_chain_put():
void tcf_chain_put(struct tcf_chain *chain)
{
if (--chain->refcnt == 0) {
tc_chain_notify(chain, NULL, 0, 0, RTM_DELCHAIN, false);
tc_chain_tmplt_del(chain);
tcf_chain_destroy(chain);
}
}
So, you only send out notification when the last refcnt is gone.
If the chain that is being deleted by a user is still used by an action,
you return 0 or -EPERM?
