On Thu, Feb 29, 2024 at 11:19 AM Paolo Abeni <pabeni@xxxxxxxxxx> wrote:
>
> On Sun, 2024-02-25 at 11:54 -0500, Jamal Hadi Salim wrote:
> > The initialisation of P4TC action instances require access to a struct
> > p4tc_act (which appears in later patches) to help us to retrieve
> > information like the P4 action parameters etc. In order to retrieve
> > struct p4tc_act we need the pipeline name or id and the action name or id.
> > Also recall that P4TC action IDs are P4 and are net namespace specific and
> > not global like standard tc actions.
> > The init callback from tc_action_ops parameters had no way of
> > supplying us that information. To solve this issue, we decided to create a
> > new tc_action_ops callback (init_ops), that provies us with the
> > tc_action_ops struct which then provides us with the pipeline and action
> > name.
>
> The new init ops looks a bit unfortunate. I *think* it would be better
> adding the new argument to the existing init op
>
Our initial goal was to avoid creating a much larger patch by changing
any other action's code and we observe that ->init() already has 8
params already ;-> And only dynamic actions need this extra extension.
If you still feel the change is needed, sure we can make that change.
> > In addition we add a new refcount to struct tc_action_ops called
> > dyn_ref, which accounts for how many action instances we have of a specific
> > action.
> >
> > Co-developed-by: Victor Nogueira <victor@xxxxxxxxxxxx>
> > Signed-off-by: Victor Nogueira <victor@xxxxxxxxxxxx>
> > Co-developed-by: Pedro Tammela <pctammela@xxxxxxxxxxxx>
> > Signed-off-by: Pedro Tammela <pctammela@xxxxxxxxxxxx>
> > Signed-off-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
> > Reviewed-by: Vlad Buslov <vladbu@xxxxxxxxxx>
> > Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
> > ---
> > include/net/act_api.h | 6 ++++++
> > net/sched/act_api.c | 14 +++++++++++---
> > 2 files changed, 17 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/net/act_api.h b/include/net/act_api.h
> > index c839ff57c..69be5ed83 100644
> > --- a/include/net/act_api.h
> > +++ b/include/net/act_api.h
> > @@ -109,6 +109,7 @@ struct tc_action_ops {
> > char kind[ACTNAMSIZ];
> > enum tca_id id; /* identifier should match kind */
> > unsigned int net_id;
> > + refcount_t p4_ref;
> > size_t size;
> > struct module *owner;
> > int (*act)(struct sk_buff *, const struct tc_action *,
> > @@ -120,6 +121,11 @@ struct tc_action_ops {
> > struct nlattr *est, struct tc_action **act,
> > struct tcf_proto *tp,
> > u32 flags, struct netlink_ext_ack *extack);
> > + /* This should be merged with the original init action */
> > + int (*init_ops)(struct net *net, struct nlattr *nla,
> > + struct nlattr *est, struct tc_action **act,
> > + struct tcf_proto *tp, struct tc_action_ops *ops,
>
> shouldn't the 'ops' argument be 'const'?
>
As it is right now this would be hard to do because we carry around a
refcnt in that struct. We will think about it..
cheers,
jamal
> Thanks,
>
> Paolo
>
