diff options
| -rw-r--r-- | include/net/net_namespace.h | 5 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 28 |
2 files changed, 33 insertions, 0 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index abb4f92456e1..ad9243afac67 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -355,8 +355,13 @@ struct pernet_operations { * synchronize_rcu() related to these pernet_operations, * instead of separate synchronize_rcu() for every net. * Please, avoid synchronize_rcu() at all, where it's possible. + * + * Note that a combination of pre_exit() and exit() can + * be used, since a synchronize_rcu() is guaranteed between + * the calls. */ int (*init)(struct net *net); + void (*pre_exit)(struct net *net); void (*exit)(struct net *net); void (*exit_batch)(struct list_head *net_exit_list); unsigned int *id; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 15f68842ac6b..89dc99a28978 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -145,6 +145,17 @@ static void ops_free(const struct pernet_operations *ops, struct net *net) } } +static void ops_pre_exit_list(const struct pernet_operations *ops, + struct list_head *net_exit_list) +{ + struct net *net; + + if (ops->pre_exit) { + list_for_each_entry(net, net_exit_list, exit_list) + ops->pre_exit(net); + } +} + static void ops_exit_list(const struct pernet_operations *ops, struct list_head *net_exit_list) { @@ -330,6 +341,12 @@ out_undo: list_add(&net->exit_list, &net_exit_list); saved_ops = ops; list_for_each_entry_continue_reverse(ops, &pernet_list, list) + ops_pre_exit_list(ops, &net_exit_list); + + synchronize_rcu(); + + saved_ops = ops; + list_for_each_entry_continue_reverse(ops, &pernet_list, list) ops_exit_list(ops, &net_exit_list); ops = saved_ops; @@ -541,10 +558,15 @@ static void cleanup_net(struct work_struct *work) list_add_tail(&net->exit_list, &net_exit_list); } + /* Run all of the network namespace pre_exit methods */ + list_for_each_entry_reverse(ops, &pernet_list, list) + ops_pre_exit_list(ops, &net_exit_list); + /* * Another CPU might be rcu-iterating the list, wait for it. * This needs to be before calling the exit() notifiers, so * the rcu_barrier() below isn't sufficient alone. + * Also the pre_exit() and exit() methods need this barrier. */ synchronize_rcu(); @@ -1101,6 +1123,8 @@ 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); return error; @@ -1115,6 +1139,8 @@ 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); } @@ -1139,6 +1165,8 @@ 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); } |