net: add phys ID compare helper to test if two IDs are the same

Signed-off-by: NScott Feldman <sfeldma@gmail.com>
Acked-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -766,6 +766,13 @@ struct netdev_phys_item_id {
 	unsigned char id_len;
 };
 
+static inline bool netdev_phys_item_id_same(struct netdev_phys_item_id *a,
+					    struct netdev_phys_item_id *b)
+{
+	return a->id_len == b->id_len &&
+	       memcmp(a->id, b->id, a->id_len) == 0;
+}
+
 typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
 				       struct sk_buff *skb);
 

net/switchdev/switchdev.c

@@ -910,13 +910,9 @@ static struct net_device *switchdev_get_dev_by_nhs(struct fib_info *fi)
 		if (switchdev_port_attr_get(dev, &attr))
 			return NULL;
 
-		if (nhsel > 0) {
-			if (prev_attr.u.ppid.id_len != attr.u.ppid.id_len)
+		if (nhsel > 0 &&
+		    !netdev_phys_item_id_same(&prev_attr.u.ppid, &attr.u.ppid))
 				return NULL;
-			if (memcmp(prev_attr.u.ppid.id, attr.u.ppid.id,
-				   attr.u.ppid.id_len))
-				return NULL;
-		}
 
 		prev_attr = attr;
 	}