Commit ee403248 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: remove default_device_exit() 



For some reason default_device_ops kept two exit method:

1) default_device_exit() is called for each netns being dismantled in
a cleanup_net() round. This acquires rtnl for each invocation.

2) default_device_exit_batch() is called once with the list of all netns
int the batch, allowing for a single rtnl invocation.

Get rid of the .exit() method to handle the logic from
default_device_exit_batch(), to decrease the number of rtnl acquisition
to one.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 16a41634

net/core/dev.c

+14 −8
Original line number Diff line number Diff line
@@ -10850,14 +10850,14 @@ static struct pernet_operations __net_initdata netdev_net_ops = { 
	.exit = netdev_exit,

};



static void __net_exit default_device_exit(struct net *net)

static void __net_exit default_device_exit_net(struct net *net)

{

	struct net_device *dev, *aux;

	/*

	 * Push all migratable network devices back to the

	 * initial network namespace

	 */

	rtnl_lock();

	ASSERT_RTNL();

	for_each_netdev_safe(net, dev, aux) {

		int err;

		char fb_name[IFNAMSIZ];
@@ -10881,22 +10881,22 @@ static void __net_exit default_device_exit(struct net *net) 
			BUG();

		}

	}

	rtnl_unlock();

}



static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)

{

	/* Return with the rtnl_lock held when there are no network

	/* Return (with the rtnl_lock held) when there are no network

	 * devices unregistering in any network namespace in net_list.

	 */

	struct net *net;

	bool unregistering;

	DEFINE_WAIT_FUNC(wait, woken_wake_function);

	bool unregistering;

	struct net *net;



	ASSERT_RTNL();

	add_wait_queue(&netdev_unregistering_wq, &wait);

	for (;;) {

		unregistering = false;

		rtnl_lock();



		list_for_each_entry(net, net_list, exit_list) {

			if (net->dev_unreg_count > 0) {

				unregistering = true;
@@ -10908,6 +10908,7 @@ static void __net_exit rtnl_lock_unregistering(struct list_head *net_list) 
		__rtnl_unlock();



		wait_woken(&wait, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);

		rtnl_lock();

	}

	remove_wait_queue(&netdev_unregistering_wq, &wait);

}
@@ -10923,6 +10924,11 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list) 
	struct net *net;

	LIST_HEAD(dev_kill_list);



	rtnl_lock();

	list_for_each_entry(net, net_list, exit_list) {

		default_device_exit_net(net);

		cond_resched();

	}

	/* To prevent network device cleanup code from dereferencing

	 * loopback devices or network devices that have been freed

	 * wait here for all pending unregistrations to complete,
@@ -10935,6 +10941,7 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list) 
	 * default_device_exit_batch.

	 */

	rtnl_lock_unregistering(net_list);



	list_for_each_entry(net, net_list, exit_list) {

		for_each_netdev_reverse(net, dev) {

			if (dev->rtnl_link_ops && dev->rtnl_link_ops->dellink)
@@ -10948,7 +10955,6 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list) 
}



static struct pernet_operations __net_initdata default_device_ops = {

	.exit = default_device_exit,

	.exit_batch = default_device_exit_batch,

};