1/*
 2 * generic net pointers
 3 */
 4
 5#ifndef __NET_GENERIC_H__
 6#define __NET_GENERIC_H__
 7
 
 8#include <linux/rcupdate.h>
 9
10/*
11 * Generic net pointers are to be used by modules to put some private
12 * stuff on the struct net without explicit struct net modification
13 *
14 * The rules are simple:
15 * 1. set pernet_operations->id.  After register_pernet_device you
16 *    will have the id of your private pointer.
17 * 2. set pernet_operations->size to have the code allocate and free
18 *    a private structure pointed to from struct net.
19 * 3. do not change this pointer while the net is alive;
20 * 4. do not try to have any private reference on the net_generic object.
21 *
22 * After accomplishing all of the above, the private pointer can be
23 * accessed with the net_generic() call.
24 */
25
26struct net_generic {
27	unsigned int len;
28	struct rcu_head rcu;
29
30	void *ptr[0];
31};
32
33static inline void *net_generic(const struct net *net, int id)
34{
35	struct net_generic *ng;
36	void *ptr;
37
38	rcu_read_lock();
39	ng = rcu_dereference(net->gen);
40	BUG_ON(id == 0 || id > ng->len);
41	ptr = ng->ptr[id - 1];
42	rcu_read_unlock();
43
 
44	return ptr;
45}
46#endif

 1/*
 2 * generic net pointers
 3 */
 4
 5#ifndef __NET_GENERIC_H__
 6#define __NET_GENERIC_H__
 7
 8#include <linux/bug.h>
 9#include <linux/rcupdate.h>
10
11/*
12 * Generic net pointers are to be used by modules to put some private
13 * stuff on the struct net without explicit struct net modification
14 *
15 * The rules are simple:
16 * 1. set pernet_operations->id.  After register_pernet_device you
17 *    will have the id of your private pointer.
18 * 2. set pernet_operations->size to have the code allocate and free
19 *    a private structure pointed to from struct net.
20 * 3. do not change this pointer while the net is alive;
21 * 4. do not try to have any private reference on the net_generic object.
22 *
23 * After accomplishing all of the above, the private pointer can be
24 * accessed with the net_generic() call.
25 */
26
27struct net_generic {
28	unsigned int len;
29	struct rcu_head rcu;
30
31	void *ptr[0];
32};
33
34static inline void *net_generic(const struct net *net, int id)
35{
36	struct net_generic *ng;
37	void *ptr;
38
39	rcu_read_lock();
40	ng = rcu_dereference(net->gen);
41	BUG_ON(id == 0 || id > ng->len);
42	ptr = ng->ptr[id - 1];
43	rcu_read_unlock();
44
45	BUG_ON(!ptr);
46	return ptr;
47}
48#endif