net: Introduce ndo_get_port_parent_id()

In preparation for getting rid of switchdev_ops, create a dedicated NDO
operation for getting the port's parent identifier. There are
essentially two classes of drivers that need to implement getting the
port's parent ID which are VF/PF drivers with a built-in switch, and
pure switchdev drivers such as mlxsw, ocelot, dsa etc.

We introduce a helper function: dev_get_port_parent_id() which supports
recursion into the lower devices to obtain the first port's parent ID.

Convert the bridge, core and ipv4 multicast routing code to check for
such ndo_get_port_parent_id() and call the helper function when valid
before falling back to switchdev_port_attr_get(). This will allow us to
convert all relevant drivers in one go instead of having to implement
both switchdev_port_attr_get() and ndo_get_port_parent_id() operations,
then get rid of switchdev_port_attr_get().

Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 57 insertions, 0 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