49 строки
1.1 KiB
C
49 строки
1.1 KiB
C
/*
|
|
* generic net pointers
|
|
*/
|
|
|
|
#ifndef __NET_GENERIC_H__
|
|
#define __NET_GENERIC_H__
|
|
|
|
#include <linux/bug.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. set pernet_operations->id. After register_pernet_device you
|
|
* will have the id of your private pointer.
|
|
* 2. set pernet_operations->size to have the code allocate and free
|
|
* a private structure pointed to from struct net.
|
|
* 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(const 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();
|
|
|
|
BUG_ON(!ptr);
|
|
return ptr;
|
|
}
|
|
#endif
|