net: dsa: remove the transactional logic from MDB entries

For many drivers, the .port_mdb_prepare callback was not a good opportunity
to avoid any error condition, and they would suppress errors found during
the actual commit phase.

Where a logical separation between the prepare and the commit phase
existed, the function that used to implement the .port_mdb_prepare
callback still exists, but now it is called directly from .port_mdb_add,
which was modified to return an int code.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Reviewed-by: Linus Wallei <linus.walleij@linaro.org> # RTL8366
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index bbf1a71..e9c517c 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -5238,27 +5238,18 @@ static enum dsa_tag_protocol mv88e6xxx_get_tag_protocol(struct dsa_switch *ds,
 	return chip->info->tag_protocol;
 }
 
-static int mv88e6xxx_port_mdb_prepare(struct dsa_switch *ds, int port,
-				      const struct switchdev_obj_port_mdb *mdb)
-{
-	/* We don't need any dynamic resource from the kernel (yet),
-	 * so skip the prepare phase.
-	 */
-
-	return 0;
-}
-
-static void mv88e6xxx_port_mdb_add(struct dsa_switch *ds, int port,
-				   const struct switchdev_obj_port_mdb *mdb)
+static int mv88e6xxx_port_mdb_add(struct dsa_switch *ds, int port,
+				  const struct switchdev_obj_port_mdb *mdb)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
+	int err;
 
 	mv88e6xxx_reg_lock(chip);
-	if (mv88e6xxx_port_db_load_purge(chip, port, mdb->addr, mdb->vid,
-					 MV88E6XXX_G1_ATU_DATA_STATE_MC_STATIC))
-		dev_err(ds->dev, "p%d: failed to load multicast MAC address\n",
-			port);
+	err = mv88e6xxx_port_db_load_purge(chip, port, mdb->addr, mdb->vid,
+					   MV88E6XXX_G1_ATU_DATA_STATE_MC_STATIC);
 	mv88e6xxx_reg_unlock(chip);
+
+	return err;
 }
 
 static int mv88e6xxx_port_mdb_del(struct dsa_switch *ds, int port,
@@ -5403,7 +5394,6 @@ static const struct dsa_switch_ops mv88e6xxx_switch_ops = {
 	.port_fdb_add           = mv88e6xxx_port_fdb_add,
 	.port_fdb_del           = mv88e6xxx_port_fdb_del,
 	.port_fdb_dump          = mv88e6xxx_port_fdb_dump,
-	.port_mdb_prepare       = mv88e6xxx_port_mdb_prepare,
 	.port_mdb_add           = mv88e6xxx_port_mdb_add,
 	.port_mdb_del           = mv88e6xxx_port_mdb_del,
 	.port_mirror_add	= mv88e6xxx_port_mirror_add,