/* SPDX-License-Identifier: GPL-2.0 */
 * 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 {
	union {
		struct {
			unsigned int len;
			struct rcu_head rcu;
		} s;

		void *ptr[0];

static inline void *net_generic(const struct net *net, unsigned int id)
	struct net_generic *ng;
	void *ptr;

	ng = rcu_dereference(net->gen);
	ptr = ng->ptr[id];

	return ptr;