net: dsa: propagate extack to .port_vlan_add

Allow drivers to communicate their restrictions to user space directly,
instead of printing to the kernel log. Where the conversion would have
been lossy and things like VLAN ID could no longer be conveyed (due to
the lack of support for printf format specifier in netlink extack), I
chose to keep the messages in full form to the kernel log only, and
leave it up to individual driver maintainers to move more messages to
extack.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 26 insertions, 10 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index f5949b39f6f7..17a9f82db937 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -75,6 +75,7 @@ struct dsa_notifier_vlan_info {
 	const struct switchdev_obj_port_vlan *vlan;
 	int sw_index;
 	int port;
+	struct netlink_ext_ack *extack;
 };
 
 /* DSA_NOTIFIER_MTU */
@@ -192,7 +193,8 @@ int dsa_port_bridge_flags(const struct dsa_port *dp,
 int dsa_port_mrouter(struct dsa_port *dp, bool mrouter,
 		     struct netlink_ext_ack *extack);
 int dsa_port_vlan_add(struct dsa_port *dp,
-		      const struct switchdev_obj_port_vlan *vlan);
+		      const struct switchdev_obj_port_vlan *vlan,
+		      struct netlink_ext_ack *extack);
 int dsa_port_vlan_del(struct dsa_port *dp,
 		      const struct switchdev_obj_port_vlan *vlan);
 int dsa_port_link_register_of(struct dsa_port *dp);
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 80e6471a7a5c..03ecefe1064a 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -535,12 +535,14 @@ int dsa_port_mdb_del(const struct dsa_port *dp,
 }
 
 int dsa_port_vlan_add(struct dsa_port *dp,
-		      const struct switchdev_obj_port_vlan *vlan)
+		      const struct switchdev_obj_port_vlan *vlan,
+		      struct netlink_ext_ack *extack)
 {
 	struct dsa_notifier_vlan_info info = {
 		.sw_index = dp->ds->index,
 		.port = dp->index,
 		.vlan = vlan,
+		.extack = extack,
 	};
 
 	return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info);
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 8c9a41a7209a..9ec487b63e13 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -357,11 +357,14 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 		rcu_read_lock();
 		err = dsa_slave_vlan_check_for_8021q_uppers(dev, &vlan);
 		rcu_read_unlock();
-		if (err)
+		if (err) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Port already has a VLAN upper with this VID");
 			return err;
+		}
 	}
 
-	err = dsa_port_vlan_add(dp, &vlan);
+	err = dsa_port_vlan_add(dp, &vlan, extack);
 	if (err)
 		return err;
 
@@ -371,7 +374,7 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 	 */
 	vlan.flags &= ~BRIDGE_VLAN_INFO_PVID;
 
-	err = dsa_port_vlan_add(dp->cpu_dp, &vlan);
+	err = dsa_port_vlan_add(dp->cpu_dp, &vlan, extack);
 	if (err)
 		return err;
 
@@ -1287,17 +1290,25 @@ static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 		/* This API only allows programming tagged, non-PVID VIDs */
 		.flags = 0,
 	};
+	struct netlink_ext_ack extack = {0};
 	int ret;
 
 	/* User port... */
-	ret = dsa_port_vlan_add(dp, &vlan);
-	if (ret)
+	ret = dsa_port_vlan_add(dp, &vlan, &extack);
+	if (ret) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
 		return ret;
+	}
 
 	/* And CPU port... */
-	ret = dsa_port_vlan_add(dp->cpu_dp, &vlan);
-	if (ret)
+	ret = dsa_port_vlan_add(dp->cpu_dp, &vlan, &extack);
+	if (ret) {
+		if (extack._msg)
+			netdev_err(dev, "CPU port %d: %s\n", dp->cpu_dp->index,
+				   extack._msg);
 		return ret;
+	}
 
 	return vlan_vid_add(master, proto, vid);
 }
diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index 1906179e59f7..c82d201181a5 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -291,7 +291,8 @@ static int dsa_switch_vlan_add(struct dsa_switch *ds,
 
 	for (port = 0; port < ds->num_ports; port++) {
 		if (dsa_switch_vlan_match(ds, port, info)) {
-			err = ds->ops->port_vlan_add(ds, port, info->vlan);
+			err = ds->ops->port_vlan_add(ds, port, info->vlan,
+						     info->extack);
 			if (err)
 				return err;
 		}