net: add net device refcount tracker to struct neighbour

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: edumazet

include/net/neighbour.h

@@ -158,6 +158,7 @@ struct neighbour {
 	struct list_head	managed_list;
 	struct rcu_head		rcu;
 	struct net_device	*dev;
+	netdevice_tracker	dev_tracker;
 	u8			primary_key[0];
 } __randomize_layout;
 

net/core/neighbour.c

@@ -624,7 +624,7 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey,
 
 	memcpy(n->primary_key, pkey, key_len);
 	n->dev = dev;
-	dev_hold(dev);
+	dev_hold_track(dev, &n->dev_tracker, GFP_ATOMIC);
 
 	/* Protocol specific setup. */
 	if (tbl->constructor &&	(error = tbl->constructor(n)) < 0) {
@@ -880,7 +880,7 @@ void neigh_destroy(struct neighbour *neigh)
 	if (dev->netdev_ops->ndo_neigh_destroy)
 		dev->netdev_ops->ndo_neigh_destroy(dev, neigh);
 
-	dev_put(dev);
+	dev_put_track(dev, &neigh->dev_tracker);
 	neigh_parms_put(neigh->parms);
 
 	neigh_dbg(2, "neigh %p is destroyed\n", neigh);