1 files changed, 49 insertions, 3 deletions

diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index 06948f536829..393f2d8a860a 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -647,15 +647,58 @@ static int dsa_switch_change_tag_proto(struct dsa_switch *ds,
 	return 0;
 }
 
-static int dsa_switch_connect_tag_proto(struct dsa_switch *ds,
-					struct dsa_notifier_tag_proto_info *info)
+/* We use the same cross-chip notifiers to inform both the tagger side, as well
+ * as the switch side, of connection and disconnection events.
+ * Since ds->tagger_data is owned by the tagger, it isn't a hard error if the
+ * switch side doesn't support connecting to this tagger, and therefore, the
+ * fact that we don't disconnect the tagger side doesn't constitute a memory
+ * leak: the tagger will still operate with persistent per-switch memory, just
+ * with the switch side unconnected to it. What does constitute a hard error is
+ * when the switch side supports connecting but fails.
+ */
+static int
+dsa_switch_connect_tag_proto(struct dsa_switch *ds,
+			     struct dsa_notifier_tag_proto_info *info)
 {
 	const struct dsa_device_ops *tag_ops = info->tag_ops;
+	int err;
+
+	/* Notify the new tagger about the connection to this switch */
+	if (tag_ops->connect) {
+		err = tag_ops->connect(ds);
+		if (err)
+			return err;
+	}
 
 	if (!ds->ops->connect_tag_protocol)
 		return -EOPNOTSUPP;
 
-	return ds->ops->connect_tag_protocol(ds, tag_ops->proto);
+	/* Notify the switch about the connection to the new tagger */
+	err = ds->ops->connect_tag_protocol(ds, tag_ops->proto);
+	if (err) {
+		/* Revert the new tagger's connection to this tree */
+		if (tag_ops->disconnect)
+			tag_ops->disconnect(ds);
+		return err;
+	}
+
+	return 0;
+}
+
+static int
+dsa_switch_disconnect_tag_proto(struct dsa_switch *ds,
+				struct dsa_notifier_tag_proto_info *info)
+{
+	const struct dsa_device_ops *tag_ops = info->tag_ops;
+
+	/* Notify the tagger about the disconnection from this switch */
+	if (tag_ops->disconnect && ds->tagger_data)
+		tag_ops->disconnect(ds);
+
+	/* No need to notify the switch, since it shouldn't have any
+	 * resources to tear down
+	 */
+	return 0;
 }
 
 static int dsa_switch_mrp_add(struct dsa_switch *ds,
@@ -780,6 +823,9 @@ static int dsa_switch_event(struct notifier_block *nb,
 	case DSA_NOTIFIER_TAG_PROTO_CONNECT:
 		err = dsa_switch_connect_tag_proto(ds, info);
 		break;
+	case DSA_NOTIFIER_TAG_PROTO_DISCONNECT:
+		err = dsa_switch_disconnect_tag_proto(ds, info);
+		break;
 	case DSA_NOTIFIER_MRP_ADD:
 		err = dsa_switch_mrp_add(ds, info);
 		break;