3 files changed, 68 insertions, 2 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index bfa4be42afff..8c6d5cf8a308 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7878,6 +7878,63 @@ int dev_get_phys_port_name(struct net_device *dev,
 EXPORT_SYMBOL(dev_get_phys_port_name);
 
 /**
+ *	dev_get_port_parent_id - Get the device's port parent identifier
+ *	@dev: network device
+ *	@ppid: pointer to a storage for the port's parent identifier
+ *	@recurse: allow/disallow recursion to lower devices
+ *
+ *	Get the devices's port parent identifier
+ */
+int dev_get_port_parent_id(struct net_device *dev,
+			   struct netdev_phys_item_id *ppid,
+			   bool recurse)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct netdev_phys_item_id first = { };
+	struct net_device *lower_dev;
+	struct list_head *iter;
+	int err = -EOPNOTSUPP;
+
+	if (ops->ndo_get_port_parent_id)
+		return ops->ndo_get_port_parent_id(dev, ppid);
+
+	if (!recurse)
+		return err;
+
+	netdev_for_each_lower_dev(dev, lower_dev, iter) {
+		err = dev_get_port_parent_id(lower_dev, ppid, recurse);
+		if (err)
+			break;
+		if (!first.id_len)
+			first = *ppid;
+		else if (memcmp(&first, ppid, sizeof(*ppid)))
+			return -ENODATA;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL(dev_get_port_parent_id);
+
+/**
+ *	netdev_port_same_parent_id - Indicate if two network devices have
+ *	the same port parent identifier
+ *	@a: first network device
+ *	@b: second network device
+ */
+bool netdev_port_same_parent_id(struct net_device *a, struct net_device *b)
+{
+	struct netdev_phys_item_id a_id = { };
+	struct netdev_phys_item_id b_id = { };
+
+	if (dev_get_port_parent_id(a, &a_id, true) ||
+	    dev_get_port_parent_id(b, &b_id, true))
+		return false;
+
+	return netdev_phys_item_id_same(&a_id, &b_id);
+}
+EXPORT_SYMBOL(netdev_port_same_parent_id);
+
+/**
  *	dev_change_proto_down - update protocol port state information
  *	@dev: device
  *	@proto_down: new value
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index ff9fd2bb4ce4..4eace9f1dcf9 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -495,6 +495,7 @@ static ssize_t phys_switch_id_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
 	struct net_device *netdev = to_net_dev(dev);
+	const struct net_device_ops *ops = netdev->netdev_ops;
 	ssize_t ret = -EINVAL;
 
 	if (!rtnl_trylock())
@@ -507,7 +508,11 @@ static ssize_t phys_switch_id_show(struct device *dev,
 			.flags = SWITCHDEV_F_NO_RECURSE,
 		};
 
-		ret = switchdev_port_attr_get(netdev, &attr);
+		if (ops->ndo_get_port_parent_id)
+			ret = dev_get_port_parent_id(netdev, &attr.u.ppid,
+						     false);
+		else
+			ret = switchdev_port_attr_get(netdev, &attr);
 		if (!ret)
 			ret = sprintf(buf, "%*phN\n", attr.u.ppid.id_len,
 				      attr.u.ppid.id);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f5a98082ac7a..90dd02c1f561 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1146,6 +1146,7 @@ static int rtnl_phys_port_name_fill(struct sk_buff *skb, struct net_device *dev)
 
 static int rtnl_phys_switch_id_fill(struct sk_buff *skb, struct net_device *dev)
 {
+	const struct net_device_ops *ops = dev->netdev_ops;
 	int err;
 	struct switchdev_attr attr = {
 		.orig_dev = dev,
@@ -1153,7 +1154,10 @@ static int rtnl_phys_switch_id_fill(struct sk_buff *skb, struct net_device *dev)
 		.flags = SWITCHDEV_F_NO_RECURSE,
 	};
 
-	err = switchdev_port_attr_get(dev, &attr);
+	if (ops->ndo_get_port_parent_id)
+		err = dev_get_port_parent_id(dev, &attr.u.ppid, false);
+	else
+		err = switchdev_port_attr_get(dev, &attr);
 	if (err) {
 		if (err == -EOPNOTSUPP)
 			return 0;