target/linux/generic/backport-5.10/724-v5.12-net-dsa-exit-early-in-dsa_slave_switchdev_event-if-w.patch

   1 From 5fb4a451a87d8ed3363d28b63a3295399373d6c4 Mon Sep 17 00:00:00 2001
   2 From: Vladimir Oltean <vladimir.oltean@nxp.com>
   3 Date: Wed, 6 Jan 2021 11:51:34 +0200
   4 Subject: [PATCH] net: dsa: exit early in dsa_slave_switchdev_event if we can't
   5  program the FDB
   6
   7 Right now, the following would happen for a switch driver that does not
   8 implement .port_fdb_add or .port_fdb_del.
   9
  10 dsa_slave_switchdev_event returns NOTIFY_OK and schedules:
  11 -> dsa_slave_switchdev_event_work
  12    -> dsa_port_fdb_add
  13       -> dsa_port_notify(DSA_NOTIFIER_FDB_ADD)
  14          -> dsa_switch_fdb_add
  15             -> if (!ds->ops->port_fdb_add) return -EOPNOTSUPP;
  16    -> an error is printed with dev_dbg, and
  17       dsa_fdb_offload_notify(switchdev_work) is not called.
  18
  19 We can avoid scheduling the worker for nothing and say NOTIFY_DONE.
  20 Because we don't call dsa_fdb_offload_notify, the static FDB entry will
  21 remain just in the software bridge.
  22
  23 Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
  24 Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
  25 Reviewed-by: Andrew Lunn <andrew@lunn.ch>
  26 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  27 ---
  28  net/dsa/slave.c | 3 +++
  29  1 file changed, 3 insertions(+)
  30
  31 --- a/net/dsa/slave.c
  32 +++ b/net/dsa/slave.c
  33 @@ -2172,6 +2172,9 @@ static int dsa_slave_switchdev_event(str
  34
  35                 dp = dsa_slave_to_port(dev);
  36
  37 +               if (!dp->ds->ops->port_fdb_add || !dp->ds->ops->port_fdb_del)
  38 +                       return NOTIFY_DONE;
  39 +
  40                 switchdev_work = kzalloc(sizeof(*switchdev_work), GFP_ATOMIC);
  41                 if (!switchdev_work)
  42                         return NOTIFY_BAD;