Commit ffabe98c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: make dev_unreg_count global 



We can use a global dev_unreg_count counter instead
of a per netns one.

As a bonus we can factorize the changes done on it
for bulk device removals.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 45a96c40

include/linux/rtnetlink.h

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ extern int rtnl_lock_killable(void); 
extern bool refcount_dec_and_rtnl_lock(refcount_t *r);



extern wait_queue_head_t netdev_unregistering_wq;

extern atomic_t dev_unreg_count;

extern struct rw_semaphore pernet_ops_rwsem;

extern struct rw_semaphore net_rwsem;

include/net/net_namespace.h

+0 −2
Original line number Diff line number Diff line
@@ -67,8 +67,6 @@ struct net { 
						 */

	spinlock_t		rules_mod_lock;



	atomic_t		dev_unreg_count;



	unsigned int		dev_base_seq;	/* protected by rtnl_mutex */

	u32			ifindex;

net/core/dev.c

+9 −3
Original line number Diff line number Diff line
@@ -9698,11 +9698,11 @@ static void dev_index_release(struct net *net, int ifindex) 
/* Delayed registration/unregisteration */

LIST_HEAD(net_todo_list);

DECLARE_WAIT_QUEUE_HEAD(netdev_unregistering_wq);

atomic_t dev_unreg_count = ATOMIC_INIT(0);



static void net_set_todo(struct net_device *dev)

{

	list_add_tail(&dev->todo_list, &net_todo_list);

	atomic_inc(&dev_net(dev)->dev_unreg_count);

}



static netdev_features_t netdev_sync_upper_features(struct net_device *lower,
@@ -10529,6 +10529,7 @@ void netdev_run_todo(void) 
{

	struct net_device *dev, *tmp;

	struct list_head list;

	int cnt;

#ifdef CONFIG_LOCKDEP

	struct list_head unlink_list;
@@ -10565,6 +10566,7 @@ void netdev_run_todo(void) 
		linkwatch_sync_dev(dev);

	}



	cnt = 0;

	while (!list_empty(&list)) {

		dev = netdev_wait_allrefs_any(&list);

		list_del(&dev->todo_list);
@@ -10582,12 +10584,13 @@ void netdev_run_todo(void) 
		if (dev->needs_free_netdev)

			free_netdev(dev);



		if (atomic_dec_and_test(&dev_net(dev)->dev_unreg_count))

			wake_up(&netdev_unregistering_wq);

		cnt++;



		/* Free network device */

		kobject_put(&dev->dev.kobj);

	}

	if (cnt && atomic_sub_and_test(cnt, &dev_unreg_count))

		wake_up(&netdev_unregistering_wq);

}



/* Convert net_device_stats to rtnl_link_stats64. rtnl_link_stats64 has
@@ -11034,6 +11037,7 @@ void unregister_netdevice_many_notify(struct list_head *head, 
{

	struct net_device *dev, *tmp;

	LIST_HEAD(close_head);

	int cnt = 0;



	BUG_ON(dev_boot_phase);

	ASSERT_RTNL();
@@ -11130,7 +11134,9 @@ void unregister_netdevice_many_notify(struct list_head *head, 
	list_for_each_entry(dev, head, unreg_list) {

		netdev_put(dev, &dev->dev_registered_tracker);

		net_set_todo(dev);

		cnt++;

	}

	atomic_add(cnt, &dev_unreg_count);



	list_del(head);

}

net/core/rtnetlink.c

+1 −10
Original line number Diff line number Diff line
@@ -483,24 +483,15 @@ EXPORT_SYMBOL_GPL(__rtnl_link_unregister); 
 */

static void rtnl_lock_unregistering_all(void)

{

	struct net *net;

	bool unregistering;

	DEFINE_WAIT_FUNC(wait, woken_wake_function);



	add_wait_queue(&netdev_unregistering_wq, &wait);

	for (;;) {

		unregistering = false;

		rtnl_lock();

		/* We held write locked pernet_ops_rwsem, and parallel

		 * setup_net() and cleanup_net() are not possible.

		 */

		for_each_net(net) {

			if (atomic_read(&net->dev_unreg_count) > 0) {

				unregistering = true;

				break;

			}

		}

		if (!unregistering)

		if (!atomic_read(&dev_unreg_count))

			break;

		__rtnl_unlock();