Commit fed176bf authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

net: Add ops_undo_single for module load/unload. 



If ops_init() fails while loading a module or we unload the
module, free_exit_list() rolls back the changes.

The rollback sequence is the same as ops_undo_list().

The ops is already removed from pernet_list before calling
free_exit_list().  If we link the ops to a temporary list,
we can reuse ops_undo_list().

Let's add a wrapper of ops_undo_list() and use it instead
of free_exit_list().

Now, we have the central place to roll back ops_init().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Link: https://patch.msgid.link/20250411205258.63164-3-kuniyu@amazon.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e333b1c3

net/core/net_namespace.c

+24 −30
Original line number Diff line number Diff line
@@ -235,6 +235,17 @@ static void ops_undo_list(const struct list_head *ops_list, 
		ops_free_list(ops, net_exit_list);

}



static void ops_undo_single(struct pernet_operations *ops,

			    struct list_head *net_exit_list)

{

	bool hold_rtnl = !!ops->exit_batch_rtnl;

	LIST_HEAD(ops_list);



	list_add(&ops->list, &ops_list);

	ops_undo_list(&ops_list, NULL, net_exit_list, false, hold_rtnl);

	list_del(&ops->list);

}



/* should be called with nsid_lock held */

static int alloc_netid(struct net *net, struct net *peer, int reqid)

{
@@ -1235,31 +1246,13 @@ void __init net_ns_init(void) 
	rtnl_register_many(net_ns_rtnl_msg_handlers);

}



static void free_exit_list(struct pernet_operations *ops, struct list_head *net_exit_list)

{

	ops_pre_exit_list(ops, net_exit_list);

	synchronize_rcu();



	if (ops->exit_batch_rtnl) {

		LIST_HEAD(dev_kill_list);



		rtnl_lock();

		ops->exit_batch_rtnl(net_exit_list, &dev_kill_list);

		unregister_netdevice_many(&dev_kill_list);

		rtnl_unlock();

	}

	ops_exit_list(ops, net_exit_list);



	ops_free_list(ops, net_exit_list);

}



#ifdef CONFIG_NET_NS

static int __register_pernet_operations(struct list_head *list,

					struct pernet_operations *ops)

{

	LIST_HEAD(net_exit_list);

	struct net *net;

	int error;

	LIST_HEAD(net_exit_list);



	list_add_tail(&ops->list, list);

	if (ops->init || ops->id) {
@@ -1278,21 +1271,21 @@ static int __register_pernet_operations(struct list_head *list, 
out_undo:

	/* If I have an error cleanup all namespaces I initialized */

	list_del(&ops->list);

	free_exit_list(ops, &net_exit_list);

	ops_undo_single(ops, &net_exit_list);

	return error;

}



static void __unregister_pernet_operations(struct pernet_operations *ops)

{

	struct net *net;

	LIST_HEAD(net_exit_list);

	struct net *net;



	list_del(&ops->list);

	/* See comment in __register_pernet_operations() */

	for_each_net(net)

		list_add_tail(&net->exit_list, &net_exit_list);



	free_exit_list(ops, &net_exit_list);

	list_del(&ops->list);

	ops_undo_single(ops, &net_exit_list);

}



#else
@@ -1300,22 +1293,23 @@ static void __unregister_pernet_operations(struct pernet_operations *ops) 
static int __register_pernet_operations(struct list_head *list,

					struct pernet_operations *ops)

{

	if (!init_net_initialized) {

	list_add_tail(&ops->list, list);



	if (!init_net_initialized)

		return 0;

	}



	return ops_init(ops, &init_net);

}



static void __unregister_pernet_operations(struct pernet_operations *ops)

{

	if (!init_net_initialized) {

	list_del(&ops->list);

	} else {



	if (init_net_initialized) {

		LIST_HEAD(net_exit_list);



		list_add(&init_net.exit_list, &net_exit_list);

		free_exit_list(ops, &net_exit_list);

		ops_undo_single(ops, &net_exit_list);

	}

}