* 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.
*
return ptr;
}
-
-extern int net_assign_generic(struct net *net, int id, void *data);
#endif
#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;
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);