netdev - [PATCH net-next 2/5] net: dsa: don't fast age bridge ports with learning turned off

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Date:   Sun,  8 Aug 2021 17:35:24 +0300
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     netdev@...r.kernel.org, Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Vladimir Oltean <olteanv@...il.com>
Subject: [PATCH net-next 2/5] net: dsa: don't fast age bridge ports with learning turned off

On topology changes, stations that were dynamically learned on ports
that are no longer part of the active topology must be flushed - this is
described by clause "17.11 Updating learned station location information"
of IEEE 802.1D-2004.

However, when address learning on the bridge port is turned off in the
first place, there is nothing to flush, so skip a potentially expensive
operation.

We can finally do this now since DSA is aware of the learning state of
its bridged ports.

Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
---
 net/dsa/port.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/dsa/port.c b/net/dsa/port.c
index d6a35a03acd6..a4c8d19a76e2 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -50,7 +50,7 @@ int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age)
 
 	ds->ops->port_stp_state_set(ds, port, state);
 
-	if (do_fast_age) {
+	if (do_fast_age && dp->learning) {
 		/* Fast age FDB entries or flush appropriate forwarding database
 		 * for the given port, if we are moving it from Learning or
 		 * Forwarding state, to Disabled or Blocking or Listening state.
-- 
2.25.1