| /* 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> |
| #include <net/net_namespace.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; |
| |
| rcu_read_lock(); |
| ng = rcu_dereference(net->gen); |
| ptr = ng->ptr[id]; |
| rcu_read_unlock(); |
| |
| return ptr; |
| } |
| #endif |