net: net_namespace: Optimize the code

There is only one caller for ops_free(), so inline it.
Separate net_drop_ns() and net_free(), so the net_free()
can be called directly.
Add free_exit_list() helper function for free net_exit_list.

====================
v2:
 - v1 does not apply, rebase it.
====================

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 9b5a767..a448a9b 100644 (file)
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -98,7 +98,7 @@ static int net_assign_generic(struct net *net, unsigned int id, void *data)
        }
 
        ng = net_alloc_generic();
-       if (ng == NULL)
+       if (!ng)
                return -ENOMEM;
 
        /*
@@ -148,13 +148,6 @@ out:
        return err;
 }
 
-static void ops_free(const struct pernet_operations *ops, struct net *net)
-{
-       if (ops->id && ops->size) {
-               kfree(net_generic(net, *ops->id));
-       }
-}
-
 static void ops_pre_exit_list(const struct pernet_operations *ops,
                              struct list_head *net_exit_list)
 {
@@ -184,7 +177,7 @@ static void ops_free_list(const struct pernet_operations *ops,
        struct net *net;
        if (ops->size && ops->id) {
                list_for_each_entry(net, net_exit_list, exit_list)
-                       ops_free(ops, net);
+                       kfree(net_generic(net, *ops->id));
        }
 }
 
@@ -433,15 +426,18 @@ out_free:
 
 static void net_free(struct net *net)
 {
-       kfree(rcu_access_pointer(net->gen));
-       kmem_cache_free(net_cachep, net);
+       if (refcount_dec_and_test(&net->passive)) {
+               kfree(rcu_access_pointer(net->gen));
+               kmem_cache_free(net_cachep, net);
+       }
 }
 
 void net_drop_ns(void *p)
 {
-       struct net *ns = p;
-       if (ns && refcount_dec_and_test(&ns->passive))
-               net_free(ns);
+       struct net *net = (struct net *)p;
+
+       if (net)
+               net_free(net);
 }
 
 struct net *copy_net_ns(unsigned long flags,
@@ -479,7 +475,7 @@ struct net *copy_net_ns(unsigned long flags,
 put_userns:
                key_remove_domain(net->key_domain);
                put_user_ns(user_ns);
-               net_drop_ns(net);
+               net_free(net);
 dec_ucounts:
                dec_net_namespaces(ucounts);
                return ERR_PTR(rv);
@@ -611,7 +607,7 @@ static void cleanup_net(struct work_struct *work)
                dec_net_namespaces(net->ucounts);
                key_remove_domain(net->key_domain);
                put_user_ns(net->user_ns);
-               net_drop_ns(net);
+               net_free(net);
        }
 }
 
@@ -1120,6 +1116,14 @@ static int __init net_ns_init(void)
 
 pure_initcall(net_ns_init);
 
+static void free_exit_list(struct pernet_operations *ops, struct list_head *net_exit_list)
+{
+       ops_pre_exit_list(ops, net_exit_list);
+       synchronize_rcu();
+       ops_exit_list(ops, net_exit_list);
+       ops_free_list(ops, net_exit_list);
+}
+
 #ifdef CONFIG_NET_NS
 static int __register_pernet_operations(struct list_head *list,
                                        struct pernet_operations *ops)
@@ -1145,10 +1149,7 @@ static int __register_pernet_operations(struct list_head *list,
 out_undo:
        /* If I have an error cleanup all namespaces I initialized */
        list_del(&ops->list);
-       ops_pre_exit_list(ops, &net_exit_list);
-       synchronize_rcu();
-       ops_exit_list(ops, &net_exit_list);
-       ops_free_list(ops, &net_exit_list);
+       free_exit_list(ops, &net_exit_list);
        return error;
 }
 
@@ -1161,10 +1162,8 @@ static void __unregister_pernet_operations(struct pernet_operations *ops)
        /* See comment in __register_pernet_operations() */
        for_each_net(net)
                list_add_tail(&net->exit_list, &net_exit_list);
-       ops_pre_exit_list(ops, &net_exit_list);
-       synchronize_rcu();
-       ops_exit_list(ops, &net_exit_list);
-       ops_free_list(ops, &net_exit_list);
+
+       free_exit_list(ops, &net_exit_list);
 }
 
 #else
@@ -1187,10 +1186,7 @@ static void __unregister_pernet_operations(struct pernet_operations *ops)
        } else {
                LIST_HEAD(net_exit_list);
                list_add(&init_net.exit_list, &net_exit_list);
-               ops_pre_exit_list(ops, &net_exit_list);
-               synchronize_rcu();
-               ops_exit_list(ops, &net_exit_list);
-               ops_free_list(ops, &net_exit_list);
+               free_exit_list(ops, &net_exit_list);
        }
 }