net: dsa: propagate switchdev vlan_filtering prepare phase to drivers

A driver may refuse to enable VLAN filtering for any reason beyond what
the DSA framework cares about, such as:
- having tc-flower rules that rely on the switch being VLAN-aware
- the particular switch does not support VLAN, even if the driver does
  (the DSA framework just checks for the presence of the .port_vlan_add
  and .port_vlan_del pointers)
- simply not supporting this configuration to be toggled at runtime

Currently, when a driver rejects a configuration it cannot support, it
does this from the commit phase, which triggers various warnings in
switchdev.

So propagate the prepare phase to drivers, to give them the ability to
refuse invalid configurations cleanly and avoid the warnings.

Since we need to modify all function prototypes and check for the
prepare phase from within the drivers, take that opportunity and move
the existing driver restrictions within the prepare phase where that is
possible and easy.

Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Woojung Huh <woojung.huh@microchip.com>
Cc: Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Landen Chao <Landen.Chao@mediatek.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Jonathan McDowell <noodles@earth.li>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 4 deletions

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index e026617d6133..a965a554ff8b 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -199,12 +199,15 @@ static int ocelot_port_set_native_vlan(struct ocelot *ocelot, int port,
 	return 0;
 }
 
-void ocelot_port_vlan_filtering(struct ocelot *ocelot, int port,
-				bool vlan_aware)
+int ocelot_port_vlan_filtering(struct ocelot *ocelot, int port,
+			       bool vlan_aware, struct switchdev_trans *trans)
 {
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
 	u32 val;
 
+	if (switchdev_trans_ph_prepare(trans))
+		return 0;
+
 	ocelot_port->vlan_aware = vlan_aware;
 
 	if (vlan_aware)
@@ -218,6 +221,8 @@ void ocelot_port_vlan_filtering(struct ocelot *ocelot, int port,
 		       ANA_PORT_VLAN_CFG, port);
 
 	ocelot_port_set_native_vlan(ocelot, port, ocelot_port->vid);
+
+	return 0;
 }
 EXPORT_SYMBOL(ocelot_port_vlan_filtering);
 
@@ -1102,12 +1107,24 @@ EXPORT_SYMBOL(ocelot_port_bridge_join);
 int ocelot_port_bridge_leave(struct ocelot *ocelot, int port,
 			     struct net_device *bridge)
 {
+	struct switchdev_trans trans;
+	int ret;
+
 	ocelot->bridge_mask &= ~BIT(port);
 
 	if (!ocelot->bridge_mask)
 		ocelot->hw_bridge_dev = NULL;
 
-	ocelot_port_vlan_filtering(ocelot, port, 0);
+	trans.ph_prepare = true;
+	ret = ocelot_port_vlan_filtering(ocelot, port, false, &trans);
+	if (ret)
+		return ret;
+
+	trans.ph_prepare = false;
+	ret = ocelot_port_vlan_filtering(ocelot, port, false, &trans);
+	if (ret)
+		return ret;
+
 	ocelot_port_set_pvid(ocelot, port, 0);
 	return ocelot_port_set_native_vlan(ocelot, port, 0);
 }
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
index 64e619f0f5b2..d3c03942546d 100644
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -790,7 +790,7 @@ static int ocelot_port_attr_set(struct net_device *dev,
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
 		ocelot_port_vlan_filtering(ocelot, port,
-					   attr->u.vlan_filtering);
+					   attr->u.vlan_filtering, trans);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED:
 		ocelot_port_attr_mc_set(ocelot, port, !attr->u.mc_disabled);