Commit 723de3eb authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

net: free altname using an RCU callback 



We had to add another synchronize_rcu() in recent fix.
Bite the bullet and add an rcu_head to netdev_name_node,
free from RCU.

Note that name_node does not hold any reference on dev
to which it points, but there must be a synchronize_rcu()
on device removal path, so we should be fine.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9e1aa985

net/core/dev.c

+16 −11
Original line number Diff line number Diff line
@@ -341,13 +341,22 @@ int netdev_name_node_alt_create(struct net_device *dev, const char *name) 
	return 0;

}



static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node)

static void netdev_name_node_alt_free(struct rcu_head *head)

{

	list_del(&name_node->list);

	struct netdev_name_node *name_node =

		container_of(head, struct netdev_name_node, rcu);



	kfree(name_node->name);

	netdev_name_node_free(name_node);

}



static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node)

{

	netdev_name_node_del(name_node);

	list_del(&name_node->list);

	call_rcu(&name_node->rcu, netdev_name_node_alt_free);

}



int netdev_name_node_alt_destroy(struct net_device *dev, const char *name)

{

	struct netdev_name_node *name_node;
@@ -362,10 +371,7 @@ int netdev_name_node_alt_destroy(struct net_device *dev, const char *name) 
	if (name_node == dev->name_node || name_node->dev != dev)

		return -EINVAL;



	netdev_name_node_del(name_node);

	synchronize_rcu();

	__netdev_name_node_alt_destroy(name_node);



	return 0;

}
@@ -373,8 +379,10 @@ static void netdev_name_node_alt_flush(struct net_device *dev) 
{

	struct netdev_name_node *name_node, *tmp;



	list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list)

		__netdev_name_node_alt_destroy(name_node);

	list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list) {

		list_del(&name_node->list);

		netdev_name_node_alt_free(&name_node->rcu);

	}

}



/* Device list insertion */
@@ -11576,11 +11584,8 @@ static void __net_exit default_device_exit_net(struct net *net) 
			snprintf(fb_name, IFNAMSIZ, "dev%%d");



		netdev_for_each_altname_safe(dev, name_node, tmp)

			if (netdev_name_in_use(&init_net, name_node->name)) {

				netdev_name_node_del(name_node);

				synchronize_rcu();

			if (netdev_name_in_use(&init_net, name_node->name))

				__netdev_name_node_alt_destroy(name_node);

			}



		err = dev_change_net_namespace(dev, &init_net, fb_name);

		if (err) {

net/core/dev.h

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ struct netdev_name_node { 
	struct list_head list;

	struct net_device *dev;

	const char *name;

	struct rcu_head rcu;

};



int netdev_get_name(struct net *net, char *name, int ifindex);