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/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 * generic net pointers
 4 */
 5
 6#ifndef __NET_GENERIC_H__
 7#define __NET_GENERIC_H__
 8
 9#include <linux/bug.h>
10#include <linux/rcupdate.h>
11
12/*
13 * Generic net pointers are to be used by modules to put some private
14 * stuff on the struct net without explicit struct net modification
15 *
16 * The rules are simple:
17 * 1. set pernet_operations->id.  After register_pernet_device you
18 *    will have the id of your private pointer.
19 * 2. set pernet_operations->size to have the code allocate and free
20 *    a private structure pointed to from struct net.
21 * 3. do not change this pointer while the net is alive;
22 * 4. do not try to have any private reference on the net_generic object.
23 *
24 * After accomplishing all of the above, the private pointer can be
25 * accessed with the net_generic() call.
26 */
27
28struct net_generic {
29	union {
30		struct {
31			unsigned int len;
32			struct rcu_head rcu;
33		} s;
34
35		void *ptr[0];
36	};
37};
38
39static inline void *net_generic(const struct net *net, unsigned int id)
40{
41	struct net_generic *ng;
42	void *ptr;
43
44	rcu_read_lock();
45	ng = rcu_dereference(net->gen);
46	ptr = ng->ptr[id];
 
47	rcu_read_unlock();
48
 
49	return ptr;
50}
51#endif