50 строки
1.2 KiB
C
50 строки
1.2 KiB
C
/*
|
|
* generic net pointers
|
|
*/
|
|
|
|
#ifndef __NET_GENERIC_H__
|
|
#define __NET_GENERIC_H__
|
|
|
|
#include <linux/rcupdate.h>
|
|
|
|
/*
|
|
* Generic net pointers are to be used by modules to put some private
|
|
* stuff on the struct net without explicit struct net modification
|
|
*
|
|
* The rules are simple:
|
|
* 1. register the ops with register_pernet_gen_device to get the id
|
|
* of your private pointer;
|
|
* 2. 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);
|
|
* 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.
|
|
*
|
|
* After accomplishing all of the above, the private pointer can be
|
|
* accessed with the net_generic() call.
|
|
*/
|
|
|
|
struct net_generic {
|
|
unsigned int len;
|
|
struct rcu_head rcu;
|
|
|
|
void *ptr[0];
|
|
};
|
|
|
|
static inline void *net_generic(struct net *net, int id)
|
|
{
|
|
struct net_generic *ng;
|
|
void *ptr;
|
|
|
|
rcu_read_lock();
|
|
ng = rcu_dereference(net->gen);
|
|
BUG_ON(id == 0 || id > ng->len);
|
|
ptr = ng->ptr[id - 1];
|
|
rcu_read_unlock();
|
|
|
|
return ptr;
|
|
}
|
|
|
|
extern int net_assign_generic(struct net *net, int id, void *data);
|
|
#endif
|