Re: [PATCH 04/14] net: sched: implement unlocked action init API

Marcelo Ricardo Leitner
2018-05-19T21:11:11Z

On Mon, May 14, 2018 at 05:16:41PM +0200, Jiri Pirko wrote:
> Mon, May 14, 2018 at 04:27:05PM CEST, vladbu@mellanox.com wrote:
> >Add additional 'unlocked' argument to act API init functions.
> >Argument is true when rtnl lock is not taken and false otherwise.
> >It is required to implement actions that need to release rtnl lock before
> >loading kernel module and reacquire if afterwards.
> >
> >Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
>
> [...]
>
>
> >@@ -721,9 +722,11 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
> > a_o = tc_lookup_action_n(act_name);
> > if (a_o == NULL) {
> > #ifdef CONFIG_MODULES
> >- rtnl_unlock();
> >+ if (!unlocked)
> >+ rtnl_unlock();
> > request_module("act_%s", act_name);
> >- rtnl_lock();
> >+ if (!unlocked)
> >+ rtnl_lock();
>
> Although I don't like this conditional locking scheme, I see no other
> way to solve this :/ But I think would be better perhaps to rename
> "unlocked" to something like "rtnl_held".

Agreed. "rtnl_held" also removes the double negation, "!un...".