netdev - [PATCH net-next] net: dsa: unregister cross-chip notifier after ds->ops->teardown

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Date:   Tue, 12 Oct 2021 15:37:35 +0300
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     netdev@...r.kernel.org, Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Vladimir Oltean <olteanv@...il.com>
Subject: [PATCH net-next] net: dsa: unregister cross-chip notifier after ds->ops->teardown

To be symmetric with the error unwind path of dsa_switch_setup(), call
dsa_switch_unregister_notifier() after ds->ops->teardown.

The implication is that ds->ops->teardown cannot emit cross-chip
notifiers. For example, currently the dsa_tag_8021q_unregister() call
from sja1105_teardown() does not propagate to the entire tree due to
this reason. However I cannot find an actual issue caused by this,
observed using code inspection.

Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
---
 net/dsa/dsa2.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 58f7dce0652c..4f92b1042dd3 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -948,11 +948,11 @@ static void dsa_switch_teardown(struct dsa_switch *ds)
 		ds->slave_mii_bus = NULL;
 	}
 
-	dsa_switch_unregister_notifier(ds);
-
 	if (ds->ops->teardown)
 		ds->ops->teardown(ds);
 
+	dsa_switch_unregister_notifier(ds);
+
 	if (ds->devlink) {
 		list_for_each_entry(dp, &ds->dst->ports, list)
 			if (dp->ds == ds)
-- 
2.25.1