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-rw-r--r--include/net/netns/generic.h9
-rw-r--r--net/core/net_namespace.c91
2 files changed, 47 insertions, 53 deletions
diff --git a/include/net/netns/generic.h b/include/net/netns/generic.h
index ff4982ab84b6..81a31c0db3e7 100644
--- a/include/net/netns/generic.h
+++ b/include/net/netns/generic.h
@@ -14,11 +14,8 @@
14 * The rules are simple: 14 * The rules are simple:
15 * 1. set pernet_operations->id. After register_pernet_device you 15 * 1. set pernet_operations->id. After register_pernet_device you
16 * will have the id of your private pointer. 16 * will have the id of your private pointer.
17 * 2. Either set pernet_operations->size (to have the code allocate and 17 * 2. set pernet_operations->size to have the code allocate and free
18 * free a private structure pointed to from struct net ) or 18 * a private structure pointed to from struct net.
19 * call net_assign_generic() to put the private data on the struct
20 * net (most preferably this should be done in the ->init callback
21 * of the ops registered);
22 * 3. do not change this pointer while the net is alive; 19 * 3. do not change this pointer while the net is alive;
23 * 4. do not try to have any private reference on the net_generic object. 20 * 4. do not try to have any private reference on the net_generic object.
24 * 21 *
@@ -46,6 +43,4 @@ static inline void *net_generic(struct net *net, int id)
46 43
47 return ptr; 44 return ptr;
48} 45}
49
50extern int net_assign_generic(struct net *net, int id, void *data);
51#endif 46#endif
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 69a20bfc527c..c988e685433a 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -27,6 +27,51 @@ EXPORT_SYMBOL(init_net);
27 27
28#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ 28#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
29 29
30static void net_generic_release(struct rcu_head *rcu)
31{
32 struct net_generic *ng;
33
34 ng = container_of(rcu, struct net_generic, rcu);
35 kfree(ng);
36}
37
38static int net_assign_generic(struct net *net, int id, void *data)
39{
40 struct net_generic *ng, *old_ng;
41
42 BUG_ON(!mutex_is_locked(&net_mutex));
43 BUG_ON(id == 0);
44
45 ng = old_ng = net->gen;
46 if (old_ng->len >= id)
47 goto assign;
48
49 ng = kzalloc(sizeof(struct net_generic) +
50 id * sizeof(void *), GFP_KERNEL);
51 if (ng == NULL)
52 return -ENOMEM;
53
54 /*
55 * Some synchronisation notes:
56 *
57 * The net_generic explores the net->gen array inside rcu
58 * read section. Besides once set the net->gen->ptr[x]
59 * pointer never changes (see rules in netns/generic.h).
60 *
61 * That said, we simply duplicate this array and schedule
62 * the old copy for kfree after a grace period.
63 */
64
65 ng->len = id;
66 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
67
68 rcu_assign_pointer(net->gen, ng);
69 call_rcu(&old_ng->rcu, net_generic_release);
70assign:
71 ng->ptr[id - 1] = data;
72 return 0;
73}
74
30static int ops_init(const struct pernet_operations *ops, struct net *net) 75static int ops_init(const struct pernet_operations *ops, struct net *net)
31{ 76{
32 int err; 77 int err;
@@ -526,49 +571,3 @@ void unregister_pernet_device(struct pernet_operations *ops)
526 mutex_unlock(&net_mutex); 571 mutex_unlock(&net_mutex);
527} 572}
528EXPORT_SYMBOL_GPL(unregister_pernet_device); 573EXPORT_SYMBOL_GPL(unregister_pernet_device);
529
530static void net_generic_release(struct rcu_head *rcu)
531{
532 struct net_generic *ng;
533
534 ng = container_of(rcu, struct net_generic, rcu);
535 kfree(ng);
536}
537
538int net_assign_generic(struct net *net, int id, void *data)
539{
540 struct net_generic *ng, *old_ng;
541
542 BUG_ON(!mutex_is_locked(&net_mutex));
543 BUG_ON(id == 0);
544
545 ng = old_ng = net->gen;
546 if (old_ng->len >= id)
547 goto assign;
548
549 ng = kzalloc(sizeof(struct net_generic) +
550 id * sizeof(void *), GFP_KERNEL);
551 if (ng == NULL)
552 return -ENOMEM;
553
554 /*
555 * Some synchronisation notes:
556 *
557 * The net_generic explores the net->gen array inside rcu
558 * read section. Besides once set the net->gen->ptr[x]
559 * pointer never changes (see rules in netns/generic.h).
560 *
561 * That said, we simply duplicate this array and schedule
562 * the old copy for kfree after a grace period.
563 */
564
565 ng->len = id;
566 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
567
568 rcu_assign_pointer(net->gen, ng);
569 call_rcu(&old_ng->rcu, net_generic_release);
570assign:
571 ng->ptr[id - 1] = data;
572 return 0;
573}
574EXPORT_SYMBOL_GPL(net_assign_generic);