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Commit 05fceb4a authored by Jiri Pirko's avatar Jiri Pirko Committed by David S. Miller
Browse files

net: disallow to use net_assign_generic externally 



Now there's no need to use this fuction directly because it's handled by
register_pernet_device. So to make this simple and easy to understand,
make this static to do not tempt potentional users.

Signed-off-by: default avatarJiri Pirko <jpirko@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 47d54d65

include/net/netns/generic.h

+2 −7
Original line number Diff line number Diff line
@@ -14,11 +14,8 @@ 
 * The rules are simple:

 * 1. set pernet_operations->id.  After register_pernet_device you

 *    will have the id of your private pointer.

 * 2. Either set pernet_operations->size (to have the code allocate and

 *    free a private structure pointed to from struct net ) or 

 *    call net_assign_generic() to put the private data on the struct

 *    net (most preferably this should be done in the ->init callback

 *    of the ops registered);

 * 2. set pernet_operations->size to have the code allocate and free

 *    a private structure pointed to from struct net.

 * 3. do not change this pointer while the net is alive;

 * 4. do not try to have any private reference on the net_generic object.

 *
@@ -46,6 +43,4 @@ static inline void *net_generic(struct net *net, int id) 


	return ptr;

}



extern int net_assign_generic(struct net *net, int id, void *data);

#endif

net/core/net_namespace.c

+45 −46
Original line number Diff line number Diff line
@@ -27,6 +27,51 @@ EXPORT_SYMBOL(init_net); 


#define INITIAL_NET_GEN_PTRS	13 /* +1 for len +2 for rcu_head */



static void net_generic_release(struct rcu_head *rcu)

{

	struct net_generic *ng;



	ng = container_of(rcu, struct net_generic, rcu);

	kfree(ng);

}



static int net_assign_generic(struct net *net, int id, void *data)

{

	struct net_generic *ng, *old_ng;



	BUG_ON(!mutex_is_locked(&net_mutex));

	BUG_ON(id == 0);



	ng = old_ng = net->gen;

	if (old_ng->len >= id)

		goto assign;



	ng = kzalloc(sizeof(struct net_generic) +

			id * sizeof(void *), GFP_KERNEL);

	if (ng == NULL)

		return -ENOMEM;



	/*

	 * Some synchronisation notes:

	 *

	 * The net_generic explores the net->gen array inside rcu

	 * read section. Besides once set the net->gen->ptr[x]

	 * pointer never changes (see rules in netns/generic.h).

	 *

	 * That said, we simply duplicate this array and schedule

	 * the old copy for kfree after a grace period.

	 */



	ng->len = id;

	memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));



	rcu_assign_pointer(net->gen, ng);

	call_rcu(&old_ng->rcu, net_generic_release);

assign:

	ng->ptr[id - 1] = data;

	return 0;

}



static int ops_init(const struct pernet_operations *ops, struct net *net)

{

	int err;
@@ -526,49 +571,3 @@ void unregister_pernet_device(struct pernet_operations *ops) 
	mutex_unlock(&net_mutex);

}

EXPORT_SYMBOL_GPL(unregister_pernet_device);
 


static void net_generic_release(struct rcu_head *rcu)

{

	struct net_generic *ng;



	ng = container_of(rcu, struct net_generic, rcu);

	kfree(ng);

}



int net_assign_generic(struct net *net, int id, void *data)

{

	struct net_generic *ng, *old_ng;



	BUG_ON(!mutex_is_locked(&net_mutex));

	BUG_ON(id == 0);



	ng = old_ng = net->gen;

	if (old_ng->len >= id)

		goto assign;



	ng = kzalloc(sizeof(struct net_generic) +

			id * sizeof(void *), GFP_KERNEL);

	if (ng == NULL)

		return -ENOMEM;



	/*

	 * Some synchronisation notes:

	 *

	 * The net_generic explores the net->gen array inside rcu

	 * read section. Besides once set the net->gen->ptr[x]

	 * pointer never changes (see rules in netns/generic.h).

	 *

	 * That said, we simply duplicate this array and schedule

	 * the old copy for kfree after a grace period.

	 */



	ng->len = id;

	memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));



	rcu_assign_pointer(net->gen, ng);

	call_rcu(&old_ng->rcu, net_generic_release);

assign:

	ng->ptr[id - 1] = data;

	return 0;

}

EXPORT_SYMBOL_GPL(net_assign_generic);