From 8518e9bb98b602eca0717d5aaad63ccbe56539d2 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Tue, 27 Mar 2018 18:02:32 +0300 Subject: [PATCH] net: Add more comments This adds comments to different places to improve readability. Signed-off-by: Kirill Tkhai Signed-off-by: David S. Miller --- include/net/net_namespace.h | 4 ++++ net/core/net_namespace.c | 2 ++ net/core/rtnetlink.c | 2 +- 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 922e8b6fb422..1ab4f920f109 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -323,6 +323,10 @@ struct pernet_operations { * have to keep in mind all other pernet_operations and * to introduce a locking, if they share common resources. * + * The only time they are called with exclusive lock is + * from register_pernet_subsys(), unregister_pernet_subsys() + * register_pernet_device() and unregister_pernet_device(). + * * Exit methods using blocking RCU primitives, such as * synchronize_rcu(), should be implemented via exit_batch. * Then, destruction of a group of net requires single diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 9e8ee4640451..b5796d17a302 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -43,6 +43,8 @@ static bool init_net_initialized; /* * pernet_ops_rwsem: protects: pernet_list, net_generic_ids, * init_net_initialized and first_device pointer. + * This is internal net namespace object. Please, don't use it + * outside. */ DECLARE_RWSEM(pernet_ops_rwsem); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 73011a60434c..2d3949789cef 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -459,7 +459,7 @@ static void rtnl_lock_unregistering_all(void) */ void rtnl_link_unregister(struct rtnl_link_ops *ops) { - /* Close the race with cleanup_net() */ + /* Close the race with setup_net() and cleanup_net() */ down_write(&pernet_ops_rwsem); rtnl_lock_unregistering_all(); __rtnl_link_unregister(ops); -- 2.30.2