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	net: Add support for batching network namespace cleanups
- Add exit_list to struct net to support building lists of network namespaces to cleanup. - Add exit_batch to pernet_operations to allow running operations only once during a network namespace exit. Instead of once per network namespace. - Factor opt ops_exit_list and ops_exit_free so the logic with cleanup up a network namespace does not need to be duplicated. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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					 2 changed files with 63 additions and 61 deletions
				
			
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			@ -43,6 +43,7 @@ struct net {
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#endif
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	struct list_head	list;		/* list of network namespaces */
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	struct list_head	cleanup_list;	/* namespaces on death row */
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	struct list_head	exit_list;	/* Use only net_mutex */
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	struct proc_dir_entry 	*proc_net;
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	struct proc_dir_entry 	*proc_net_stat;
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			@ -236,6 +237,7 @@ struct pernet_operations {
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	struct list_head list;
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	int (*init)(struct net *net);
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	void (*exit)(struct net *net);
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	void (*exit_batch)(struct list_head *net_exit_list);
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	int *id;
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	size_t size;
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};
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			@ -70,6 +70,36 @@ static void ops_free(const struct pernet_operations *ops, struct net *net)
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	}
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}
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static void ops_exit_list(const struct pernet_operations *ops,
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			  struct list_head *net_exit_list)
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{
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	struct net *net;
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	if (ops->exit) {
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		list_for_each_entry(net, net_exit_list, exit_list)
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			ops->exit(net);
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	}
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	if (&ops->list == first_device) {
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		LIST_HEAD(dev_kill_list);
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		rtnl_lock();
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		list_for_each_entry(net, net_exit_list, exit_list)
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			unregister_netdevices(net, &dev_kill_list);
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		unregister_netdevice_many(&dev_kill_list);
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		rtnl_unlock();
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	}
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	if (ops->exit_batch)
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		ops->exit_batch(net_exit_list);
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}
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static void ops_free_list(const struct pernet_operations *ops,
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			  struct list_head *net_exit_list)
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{
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	struct net *net;
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	if (ops->size && ops->id) {
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		list_for_each_entry(net, net_exit_list, exit_list)
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			ops_free(ops, net);
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	}
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}
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/*
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 * setup_net runs the initializers for the network namespace object.
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 */
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			@ -78,6 +108,7 @@ static __net_init int setup_net(struct net *net)
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	/* Must be called with net_mutex held */
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	const struct pernet_operations *ops, *saved_ops;
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	int error = 0;
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	LIST_HEAD(net_exit_list);
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	atomic_set(&net->count, 1);
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			@ -97,21 +128,14 @@ static __net_init int setup_net(struct net *net)
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	/* Walk through the list backwards calling the exit functions
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	 * for the pernet modules whose init functions did not fail.
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	 */
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	list_add(&net->exit_list, &net_exit_list);
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	saved_ops = ops;
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	list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
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		if (ops->exit)
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			ops->exit(net);
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		if (&ops->list == first_device) {
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			LIST_HEAD(dev_kill_list);
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			rtnl_lock();
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			unregister_netdevices(net, &dev_kill_list);
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			unregister_netdevice_many(&dev_kill_list);
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			rtnl_unlock();
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		}
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	}
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	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
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		ops_exit_list(ops, &net_exit_list);
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	ops = saved_ops;
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	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
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		ops_free(ops, net);
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		ops_free_list(ops, &net_exit_list);
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	rcu_barrier();
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	goto out;
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			@ -207,6 +231,7 @@ static void cleanup_net(struct work_struct *work)
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	const struct pernet_operations *ops;
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	struct net *net, *tmp;
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	LIST_HEAD(net_kill_list);
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	LIST_HEAD(net_exit_list);
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	/* Atomically snapshot the list of namespaces to cleanup */
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	spin_lock_irq(&cleanup_list_lock);
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			@ -217,8 +242,10 @@ static void cleanup_net(struct work_struct *work)
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	/* Don't let anyone else find us. */
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	rtnl_lock();
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	list_for_each_entry(net, &net_kill_list, cleanup_list)
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	list_for_each_entry(net, &net_kill_list, cleanup_list) {
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		list_del_rcu(&net->list);
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		list_add_tail(&net->exit_list, &net_exit_list);
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	}
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	rtnl_unlock();
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	/*
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			@ -229,27 +256,12 @@ static void cleanup_net(struct work_struct *work)
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	synchronize_rcu();
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	/* Run all of the network namespace exit methods */
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	list_for_each_entry_reverse(ops, &pernet_list, list) {
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		if (ops->exit) {
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			list_for_each_entry(net, &net_kill_list, cleanup_list)
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				ops->exit(net);
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		}
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		if (&ops->list == first_device) {
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			LIST_HEAD(dev_kill_list);
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			rtnl_lock();
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			list_for_each_entry(net, &net_kill_list, cleanup_list)
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				unregister_netdevices(net, &dev_kill_list);
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			unregister_netdevice_many(&dev_kill_list);
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			rtnl_unlock();
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		}
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	}
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	list_for_each_entry_reverse(ops, &pernet_list, list)
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		ops_exit_list(ops, &net_exit_list);
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	/* Free the net generic variables */
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	list_for_each_entry_reverse(ops, &pernet_list, list) {
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		if (ops->size && ops->id) {
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			list_for_each_entry(net, &net_kill_list, cleanup_list)
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				ops_free(ops, net);
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		}
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	}
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	list_for_each_entry_reverse(ops, &pernet_list, list)
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		ops_free_list(ops, &net_exit_list);
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	mutex_unlock(&net_mutex);
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			@ -259,8 +271,8 @@ static void cleanup_net(struct work_struct *work)
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	rcu_barrier();
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	/* Finally it is safe to free my network namespace structure */
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	list_for_each_entry_safe(net, tmp, &net_kill_list, cleanup_list) {
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		list_del_init(&net->cleanup_list);
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	list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
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		list_del_init(&net->exit_list);
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		net_free(net);
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	}
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}
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			@ -348,8 +360,9 @@ pure_initcall(net_ns_init);
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static int __register_pernet_operations(struct list_head *list,
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					struct pernet_operations *ops)
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{
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	struct net *net, *undo_net;
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	struct net *net;
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	int error;
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	LIST_HEAD(net_exit_list);
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	list_add_tail(&ops->list, list);
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	if (ops->init || (ops->id && ops->size)) {
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			@ -357,6 +370,7 @@ static int __register_pernet_operations(struct list_head *list,
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			error = ops_init(ops, net);
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			if (error)
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				goto out_undo;
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			list_add_tail(&net->exit_list, &net_exit_list);
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		}
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	}
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	return 0;
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			@ -364,36 +378,21 @@ static int __register_pernet_operations(struct list_head *list,
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out_undo:
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	/* If I have an error cleanup all namespaces I initialized */
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	list_del(&ops->list);
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	if (ops->exit) {
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		for_each_net(undo_net) {
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			if (net_eq(undo_net, net))
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				goto undone;
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			ops->exit(undo_net);
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		}
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	}
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undone:
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	if (ops->size && ops->id) {
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		for_each_net(undo_net) {
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			if (net_eq(undo_net, net))
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				goto freed;
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			ops_free(ops, undo_net);
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		}
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	}
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freed:
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	ops_exit_list(ops, &net_exit_list);
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	ops_free_list(ops, &net_exit_list);
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	return error;
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}
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static void __unregister_pernet_operations(struct pernet_operations *ops)
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{
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	struct net *net;
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	LIST_HEAD(net_exit_list);
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	list_del(&ops->list);
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	if (ops->exit)
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		for_each_net(net)
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			ops->exit(net);
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	if (ops->id && ops->size)
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		for_each_net(net)
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			ops_free(ops, net);
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	for_each_net(net)
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		list_add_tail(&net->exit_list, &net_exit_list);
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	ops_exit_list(ops, &net_exit_list);
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	ops_free_list(ops, &net_exit_list);
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}
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#else
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			@ -411,9 +410,10 @@ static int __register_pernet_operations(struct list_head *list,
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static void __unregister_pernet_operations(struct pernet_operations *ops)
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{
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	if (ops->exit)
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		ops->exit(&init_net);
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	ops_free(ops, &init_net);
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	LIST_HEAD(net_exit_list);
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	list_add(&init_net.exit_list, &net_exit_list);
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	ops_exit_list(ops, &net_exit_list);
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	ops_free_list(ops, &net_exit_list);
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}
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#endif /* CONFIG_NET_NS */
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