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

 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	union {
29		struct {
30			unsigned int len;
31			struct rcu_head rcu;
32		} s;
33
34		void *ptr[0];
35	};
36};
37
38static inline void *net_generic(const struct net *net, unsigned int id)
39{
40	struct net_generic *ng;
41	void *ptr;
42
43	rcu_read_lock();
44	ng = rcu_dereference(net->gen);
45	ptr = ng->ptr[id];
 
46	rcu_read_unlock();
47
 
48	return ptr;
49}
50#endif