Re: [patch net-next 6/7] net: dsa: don't do devlink port setup early

Vladimir Oltean
2022-08-25T22:47:34Z

On Thu, Aug 25, 2022 at 12:33:59PM +0200, Jiri Pirko wrote:
> Note there is no longer needed to reinit port as unused if
> dsa_port_setup() fails, as it unregisters the devlink port instance on
> the error path.
> @@ -957,8 +941,6 @@ static void dsa_switch_teardown(struct dsa_switch *ds)
> dsa_switch_unregister_notifier(ds);
>
> if (ds->devlink) {
> - dsa_switch_for_each_port(dp, ds)
> - dsa_port_devlink_teardown(dp);
> devlink_free(ds->devlink);
> ds->devlink = NULL;
> }
> @@ -1010,11 +992,8 @@ static int dsa_tree_setup_ports(struct dsa_switch_tree *dst)
> list_for_each_entry(dp, &dst->ports, list) {
> if (dsa_port_is_user(dp) || dsa_port_is_unused(dp)) {
> err = dsa_port_setup(dp);
> - if (err) {
> - err = dsa_port_reinit_as_unused(dp);
> - if (err)
> - goto teardown;
> - }
> + if (err)
> + goto teardown;
> }
> }

Please don't delete this, there is still a need.

First of all, dsa_port_setup() for user ports must not fail the probing
of the switch - see commit 86f8b1c01a0a ("net: dsa: Do not make user
port errors fatal").

Also, DSA exposes devlink regions for unused ports too - those have the
{DSA_PORT_TYPE,DEVLINK_PORT_FLAVOUR}_UNUSED flavor.

I also see some weird behavior when I intentionally break the probing of
some ports, but I haven't debugged to see exactly why, and it's likely
I won't have time to debug this week.