Commit 273c28bc authored by Kirill Tkhai's avatar Kirill Tkhai Committed by David S. Miller
Browse files

net: Convert atomic_t net::count to refcount_t 



Since net could be obtained from RCU lists,
and there is a race with net destruction,
the patch converts net::count to refcount_t.

This provides sanity checks for the cases of
incrementing counter of already dead net,
when maybe_get_net() has to used instead
of get_net().

Drivers: allyesconfig and allmodconfig are OK.

Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 594831a8

include/net/net_namespace.h

+4 −4
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ struct net { 
	refcount_t		passive;	/* To decided when the network

						 * namespace should be freed.

						 */

	atomic_t		count;		/* To decided when the network

	refcount_t		count;		/* To decided when the network

						 *  namespace should be shut down.

						 */

	spinlock_t		rules_mod_lock;
@@ -195,7 +195,7 @@ void __put_net(struct net *net); 


static inline struct net *get_net(struct net *net)

{

	atomic_inc(&net->count);

	refcount_inc(&net->count);

	return net;

}
@@ -206,14 +206,14 @@ static inline struct net *maybe_get_net(struct net *net) 
	 * exists.  If the reference count is zero this

	 * function fails and returns NULL.

	 */

	if (!atomic_inc_not_zero(&net->count))

	if (!refcount_inc_not_zero(&net->count))

		net = NULL;

	return net;

}



static inline void put_net(struct net *net)

{

	if (atomic_dec_and_test(&net->count))

	if (refcount_dec_and_test(&net->count))

		__put_net(net);

}

net/core/net-sysfs.c

+3 −3
Original line number Diff line number Diff line
@@ -961,7 +961,7 @@ net_rx_queue_update_kobjects(struct net_device *dev, int old_num, int new_num) 
	while (--i >= new_num) {

		struct kobject *kobj = &dev->_rx[i].kobj;



		if (!atomic_read(&dev_net(dev)->count))

		if (!refcount_read(&dev_net(dev)->count))

			kobj->uevent_suppress = 1;

		if (dev->sysfs_rx_queue_group)

			sysfs_remove_group(kobj, dev->sysfs_rx_queue_group);
@@ -1367,7 +1367,7 @@ netdev_queue_update_kobjects(struct net_device *dev, int old_num, int new_num) 
	while (--i >= new_num) {

		struct netdev_queue *queue = dev->_tx + i;



		if (!atomic_read(&dev_net(dev)->count))

		if (!refcount_read(&dev_net(dev)->count))

			queue->kobj.uevent_suppress = 1;

#ifdef CONFIG_BQL

		sysfs_remove_group(&queue->kobj, &dql_group);
@@ -1558,7 +1558,7 @@ void netdev_unregister_kobject(struct net_device *ndev) 
{

	struct device *dev = &ndev->dev;



	if (!atomic_read(&dev_net(ndev)->count))

	if (!refcount_read(&dev_net(ndev)->count))

		dev_set_uevent_suppress(dev, 1);



	kobject_get(&dev->kobj);

net/core/net_namespace.c

+4 −4
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ LIST_HEAD(net_namespace_list); 
EXPORT_SYMBOL_GPL(net_namespace_list);



struct net init_net = {

	.count		= ATOMIC_INIT(1),

	.count		= REFCOUNT_INIT(1),

	.dev_base_head	= LIST_HEAD_INIT(init_net.dev_base_head),

};

EXPORT_SYMBOL(init_net);
@@ -224,10 +224,10 @@ int peernet2id_alloc(struct net *net, struct net *peer) 
	bool alloc;

	int id;



	if (atomic_read(&net->count) == 0)

	if (refcount_read(&net->count) == 0)

		return NETNSA_NSID_NOT_ASSIGNED;

	spin_lock_bh(&net->nsid_lock);

	alloc = atomic_read(&peer->count) == 0 ? false : true;

	alloc = refcount_read(&peer->count) == 0 ? false : true;

	id = __peernet2id_alloc(net, peer, &alloc);

	spin_unlock_bh(&net->nsid_lock);

	if (alloc && id >= 0)
@@ -284,7 +284,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 
	int error = 0;

	LIST_HEAD(net_exit_list);



	atomic_set(&net->count, 1);

	refcount_set(&net->count, 1);

	refcount_set(&net->passive, 1);

	net->dev_base_seq = 1;

	net->user_ns = user_ns;

net/ipv4/inet_timewait_sock.c

+2 −2
Original line number Diff line number Diff line
@@ -270,14 +270,14 @@ restart: 
				continue;

			tw = inet_twsk(sk);

			if ((tw->tw_family != family) ||

				atomic_read(&twsk_net(tw)->count))

				refcount_read(&twsk_net(tw)->count))

				continue;



			if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))

				continue;



			if (unlikely((tw->tw_family != family) ||

				     atomic_read(&twsk_net(tw)->count))) {

				     refcount_read(&twsk_net(tw)->count))) {

				inet_twsk_put(tw);

				goto restart;

			}

net/ipv4/tcp_metrics.c

+1 −1
Original line number Diff line number Diff line
@@ -892,7 +892,7 @@ static void tcp_metrics_flush_all(struct net *net) 
		pp = &hb->chain;

		for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {

			match = net ? net_eq(tm_net(tm), net) :

				!atomic_read(&tm_net(tm)->count);

				!refcount_read(&tm_net(tm)->count);

			if (match) {

				*pp = tm->tcpm_next;

				kfree_rcu(tm, rcu_head);

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