netns: add register_pernet_gen_subsys/unregister_pernet_gen_subsys
netns ops which are registered with register_pernet_gen_device() are
shutdown strictly before those which are registered with
register_pernet_subsys(). Sometimes this leads to opposite (read: buggy)
shutdown ordering between two modules.
Add register_pernet_gen_subsys()/unregister_pernet_gen_subsys() for modules
which aren't elite enough for entry in struct net, and which can't use
register_pernet_gen_device(). PPTP conntracking module is such one.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index f1d07b5..1895a4c 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -325,6 +325,38 @@
}
EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
+int register_pernet_gen_subsys(int *id, struct pernet_operations *ops)
+{
+ int rv;
+
+ mutex_lock(&net_mutex);
+again:
+ rv = ida_get_new_above(&net_generic_ids, 1, id);
+ if (rv < 0) {
+ if (rv == -EAGAIN) {
+ ida_pre_get(&net_generic_ids, GFP_KERNEL);
+ goto again;
+ }
+ goto out;
+ }
+ rv = register_pernet_operations(first_device, ops);
+ if (rv < 0)
+ ida_remove(&net_generic_ids, *id);
+ mutex_unlock(&net_mutex);
+out:
+ return rv;
+}
+EXPORT_SYMBOL_GPL(register_pernet_gen_subsys);
+
+void unregister_pernet_gen_subsys(int id, struct pernet_operations *ops)
+{
+ mutex_lock(&net_mutex);
+ unregister_pernet_operations(ops);
+ ida_remove(&net_generic_ids, id);
+ mutex_unlock(&net_mutex);
+}
+EXPORT_SYMBOL_GPL(unregister_pernet_gen_subsys);
+
/**
* register_pernet_device - register a network namespace device
* @ops: pernet operations structure for the subsystem