net: dsa: propagate extack to port_lag_join

Drivers could refuse to offload a LAG configuration for a variety of
reasons, mainly having to do with its TX type. Additionally, since DSA
masters may now also be LAG interfaces, and this will translate into a
call to port_lag_join on the CPU ports, there may be extra restrictions
there. Propagate the netlink extack to this DSA method in order for
drivers to give a meaningful error message back to the user.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: vladimiroltean

drivers/net/dsa/mv88e6xxx/chip.c

@@ -6593,14 +6593,17 @@ static int mv88e6xxx_port_bridge_flags(struct dsa_switch *ds, int port,
 
 static bool mv88e6xxx_lag_can_offload(struct dsa_switch *ds,
 				      struct dsa_lag lag,
-				      struct netdev_lag_upper_info *info)
+				      struct netdev_lag_upper_info *info,
+				      struct netlink_ext_ack *extack)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
 	struct dsa_port *dp;
 	int members = 0;
 
-	if (!mv88e6xxx_has_lag(chip))
+	if (!mv88e6xxx_has_lag(chip)) {
+		NL_SET_ERR_MSG_MOD(extack, "Chip does not support LAG offload");
 		return false;
+	}
 
 	if (!lag.id)
 		return false;
@@ -6609,14 +6612,20 @@ static bool mv88e6xxx_lag_can_offload(struct dsa_switch *ds,
 		/* Includes the port joining the LAG */
 		members++;
 
-	if (members > 8)
+	if (members > 8) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Cannot offload more than 8 LAG ports");
 		return false;
+	}
 
 	/* We could potentially relax this to include active
 	 * backup in the future.
 	 */
-	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH)
+	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Can only offload LAG using hash TX type");
 		return false;
+	}
 
 	/* Ideally we would also validate that the hash type matches
 	 * the hardware. Alas, this is always set to unknown on team
@@ -6769,12 +6778,13 @@ static int mv88e6xxx_port_lag_change(struct dsa_switch *ds, int port)
 
 static int mv88e6xxx_port_lag_join(struct dsa_switch *ds, int port,
 				   struct dsa_lag lag,
-				   struct netdev_lag_upper_info *info)
+				   struct netdev_lag_upper_info *info,
+				   struct netlink_ext_ack *extack)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
 	int err, id;
 
-	if (!mv88e6xxx_lag_can_offload(ds, lag, info))
+	if (!mv88e6xxx_lag_can_offload(ds, lag, info, extack))
 		return -EOPNOTSUPP;
 
 	/* DSA LAG IDs are one-based */
@@ -6827,12 +6837,13 @@ static int mv88e6xxx_crosschip_lag_change(struct dsa_switch *ds, int sw_index,
 
 static int mv88e6xxx_crosschip_lag_join(struct dsa_switch *ds, int sw_index,
 					int port, struct dsa_lag lag,
-					struct netdev_lag_upper_info *info)
+					struct netdev_lag_upper_info *info,
+					struct netlink_ext_ack *extack)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
 	int err;
 
-	if (!mv88e6xxx_lag_can_offload(ds, lag, info))
+	if (!mv88e6xxx_lag_can_offload(ds, lag, info, extack))
 		return -EOPNOTSUPP;
 
 	mv88e6xxx_reg_lock(chip);

drivers/net/dsa/ocelot/felix.c

@@ -861,11 +861,12 @@ static void felix_bridge_leave(struct dsa_switch *ds, int port,
 
 static int felix_lag_join(struct dsa_switch *ds, int port,
 			  struct dsa_lag lag,
-			  struct netdev_lag_upper_info *info)
+			  struct netdev_lag_upper_info *info,
+			  struct netlink_ext_ack *extack)
 {
 	struct ocelot *ocelot = ds->priv;
 
-	return ocelot_port_lag_join(ocelot, port, lag.dev, info);
+	return ocelot_port_lag_join(ocelot, port, lag.dev, info, extack);
 }
 
 static int felix_lag_leave(struct dsa_switch *ds, int port,

drivers/net/dsa/qca/qca8k-common.c

@@ -1017,7 +1017,8 @@ int qca8k_port_vlan_del(struct dsa_switch *ds, int port,
 
 static bool qca8k_lag_can_offload(struct dsa_switch *ds,
 				  struct dsa_lag lag,
-				  struct netdev_lag_upper_info *info)
+				  struct netdev_lag_upper_info *info,
+				  struct netlink_ext_ack *extack)
 {
 	struct dsa_port *dp;
 	int members = 0;
@@ -1029,15 +1030,24 @@ static bool qca8k_lag_can_offload(struct dsa_switch *ds,
 		/* Includes the port joining the LAG */
 		members++;
 
-	if (members > QCA8K_NUM_PORTS_FOR_LAG)
+	if (members > QCA8K_NUM_PORTS_FOR_LAG) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Cannot offload more than 4 LAG ports");
 		return false;
+	}
 
-	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH)
+	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Can only offload LAG using hash TX type");
 		return false;
+	}
 
 	if (info->hash_type != NETDEV_LAG_HASH_L2 &&
-	    info->hash_type != NETDEV_LAG_HASH_L23)
+	    info->hash_type != NETDEV_LAG_HASH_L23) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Can only offload L2 or L2+L3 TX hash");
 		return false;
+	}
 
 	return true;
 }
@@ -1160,11 +1170,12 @@ static int qca8k_lag_refresh_portmap(struct dsa_switch *ds, int port,
 }
 
 int qca8k_port_lag_join(struct dsa_switch *ds, int port, struct dsa_lag lag,
-			struct netdev_lag_upper_info *info)
+			struct netdev_lag_upper_info *info,
+			struct netlink_ext_ack *extack)
 {
 	int ret;
 
-	if (!qca8k_lag_can_offload(ds, lag, info))
+	if (!qca8k_lag_can_offload(ds, lag, info, extack))
 		return -EOPNOTSUPP;
 
 	ret = qca8k_lag_setup_hash(ds, lag, info);

drivers/net/dsa/qca/qca8k.h

@@ -512,7 +512,8 @@ int qca8k_port_vlan_del(struct dsa_switch *ds, int port,
 
 /* Common port LAG function */
 int qca8k_port_lag_join(struct dsa_switch *ds, int port, struct dsa_lag lag,
-			struct netdev_lag_upper_info *info);
+			struct netdev_lag_upper_info *info,
+			struct netlink_ext_ack *extack);
 int qca8k_port_lag_leave(struct dsa_switch *ds, int port,
 			 struct dsa_lag lag);
 

drivers/net/ethernet/mscc/ocelot.c

@@ -2132,10 +2132,14 @@ static void ocelot_migrate_lag_fdbs(struct ocelot *ocelot,
 
 int ocelot_port_lag_join(struct ocelot *ocelot, int port,
 			 struct net_device *bond,
-			 struct netdev_lag_upper_info *info)
+			 struct netdev_lag_upper_info *info,
+			 struct netlink_ext_ack *extack)
 {
-	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH)
+	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Can only offload LAG using hash TX type");
 		return -EOPNOTSUPP;
+	}
 
 	mutex_lock(&ocelot->fwd_domain_lock);
 

drivers/net/ethernet/mscc/ocelot_net.c

@@ -1412,11 +1412,10 @@ static int ocelot_netdevice_lag_join(struct net_device *dev,
 	int port = priv->port.index;
 	int err;
 
-	err = ocelot_port_lag_join(ocelot, port, bond, info);
-	if (err == -EOPNOTSUPP) {
-		NL_SET_ERR_MSG_MOD(extack, "Offloading not supported");
+	err = ocelot_port_lag_join(ocelot, port, bond, info, extack);
+	if (err == -EOPNOTSUPP)
+		/* Offloading not supported, fall back to software LAG */
 		return 0;
-	}
 
 	bridge_dev = netdev_master_upper_dev_get(bond);
 	if (!bridge_dev || !netif_is_bridge_master(bridge_dev))

include/net/dsa.h

@@ -1094,7 +1094,8 @@ struct dsa_switch_ops {
 					int port);
 	int	(*crosschip_lag_join)(struct dsa_switch *ds, int sw_index,
 				      int port, struct dsa_lag lag,
-				      struct netdev_lag_upper_info *info);
+				      struct netdev_lag_upper_info *info,
+				      struct netlink_ext_ack *extack);
 	int	(*crosschip_lag_leave)(struct dsa_switch *ds, int sw_index,
 				       int port, struct dsa_lag lag);
 
@@ -1169,7 +1170,8 @@ struct dsa_switch_ops {
 	int	(*port_lag_change)(struct dsa_switch *ds, int port);
 	int	(*port_lag_join)(struct dsa_switch *ds, int port,
 				 struct dsa_lag lag,
-				 struct netdev_lag_upper_info *info);
+				 struct netdev_lag_upper_info *info,
+				 struct netlink_ext_ack *extack);
 	int	(*port_lag_leave)(struct dsa_switch *ds, int port,
 				  struct dsa_lag lag);
 

include/soc/mscc/ocelot.h

@@ -1229,7 +1229,8 @@ int ocelot_port_mdb_del(struct ocelot *ocelot, int port,
 			const struct net_device *bridge);
 int ocelot_port_lag_join(struct ocelot *ocelot, int port,
 			 struct net_device *bond,
-			 struct netdev_lag_upper_info *info);
+			 struct netdev_lag_upper_info *info,
+			 struct netlink_ext_ack *extack);
 void ocelot_port_lag_leave(struct ocelot *ocelot, int port,
 			   struct net_device *bond);
 void ocelot_port_lag_change(struct ocelot *ocelot, int port, bool lag_tx_active);

net/dsa/dsa_priv.h

@@ -88,6 +88,7 @@ struct dsa_notifier_lag_info {
 	const struct dsa_port *dp;
 	struct dsa_lag lag;
 	struct netdev_lag_upper_info *info;
+	struct netlink_ext_ack *extack;
 };
 
 /* DSA_NOTIFIER_VLAN_* */

net/dsa/port.c

@@ -635,6 +635,7 @@ int dsa_port_lag_join(struct dsa_port *dp, struct net_device *lag_dev,
 	struct dsa_notifier_lag_info info = {
 		.dp = dp,
 		.info = uinfo,
+		.extack = extack,
 	};
 	struct net_device *bridge_dev;
 	int err;