From 19efbd93e6fb05eab81856b4fc8d64211dd37088 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Mon, 19 Feb 2018 12:58:38 +0300 Subject: net: Kill net_mutex We take net_mutex, when there are !async pernet_operations registered, and read locking of net_sem is not enough. But we may get rid of taking the mutex, and just change the logic to write lock net_sem in such cases. This obviously reduces the number of lock operations, we do. Signed-off-by: Kirill Tkhai Signed-off-by: David S. Miller --- include/linux/rtnetlink.h | 1 - include/net/net_namespace.h | 11 +++++++---- 2 files changed, 7 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index e9ee9ad0a681..3573b4bf2fdf 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -35,7 +35,6 @@ extern int rtnl_trylock(void); extern int rtnl_is_locked(void); extern wait_queue_head_t netdev_unregistering_wq; -extern struct mutex net_mutex; extern struct rw_semaphore net_sem; #ifdef CONFIG_PROVE_LOCKING diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 9158ec1ad06f..115b01b92f4d 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -60,8 +60,11 @@ struct net { struct list_head list; /* list of network namespaces */ struct list_head cleanup_list; /* namespaces on death row */ - struct list_head exit_list; /* Use only net_mutex */ - + struct list_head exit_list; /* To linked to call pernet exit + * methods on dead net (net_sem + * read locked), or to unregister + * pernet ops (net_sem wr locked). + */ struct user_namespace *user_ns; /* Owning user namespace */ struct ucounts *ucounts; spinlock_t nsid_lock; @@ -89,7 +92,7 @@ struct net { /* core fib_rules */ struct list_head rules_ops; - struct list_head fib_notifier_ops; /* protected by net_mutex */ + struct list_head fib_notifier_ops; /* protected by net_sem */ struct net_device *loopback_dev; /* The loopback */ struct netns_core core; @@ -316,7 +319,7 @@ struct pernet_operations { /* * Indicates above methods are allowed to be executed in parallel * with methods of any other pernet_operations, i.e. they are not - * need synchronization via net_mutex. + * need write locked net_sem. */ bool async; }; -- cgit v1.2.3-70-g09d2