From 2f635ceeb22ba13c307236d69795fbb29cfa3e7c Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Tue, 27 Mar 2018 18:02:13 +0300 Subject: net: Drop pernet_operations::async Synchronous pernet_operations are not allowed anymore. All are asynchronous. So, drop the structure member. Signed-off-by: Kirill Tkhai Signed-off-by: David S. Miller --- include/net/net_namespace.h | 6 ------ 1 file changed, 6 deletions(-) (limited to 'include') diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 09e30bdc7876..37bcf8382b61 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -333,12 +333,6 @@ struct pernet_operations { void (*exit_batch)(struct list_head *net_exit_list); unsigned int *id; size_t size; - /* - * Indicates above methods are allowed to be executed in parallel - * with methods of any other pernet_operations, i.e. they are not - * need write locked net_sem. - */ - bool async; }; /* -- cgit v1.2.3 From 4420bf21fb6c0306e36ad58ade1e741fba57ce65 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Tue, 27 Mar 2018 18:02:23 +0300 Subject: net: Rename net_sem to pernet_ops_rwsem net_sem is some undefined area name, so it will be better to make the area more defined. Rename it to pernet_ops_rwsem for better readability and better intelligibility. Signed-off-by: Kirill Tkhai Signed-off-by: David S. Miller --- include/linux/rtnetlink.h | 2 +- include/net/net_namespace.h | 12 +++++++----- net/core/net_namespace.c | 40 ++++++++++++++++++++-------------------- net/core/rtnetlink.c | 4 ++-- 4 files changed, 30 insertions(+), 28 deletions(-) (limited to 'include') diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 562a175c35a9..c7d1e4689325 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -36,7 +36,7 @@ extern int rtnl_is_locked(void); extern int rtnl_lock_killable(void); extern wait_queue_head_t netdev_unregistering_wq; -extern struct rw_semaphore net_sem; +extern struct rw_semaphore pernet_ops_rwsem; #ifdef CONFIG_PROVE_LOCKING extern bool lockdep_rtnl_is_held(void); diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 37bcf8382b61..922e8b6fb422 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -60,9 +60,10 @@ struct net { struct list_head list; /* list of network namespaces */ 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). + * methods on dead net ( + * pernet_ops_rwsem read locked), + * or to unregister pernet ops + * (pernet_ops_rwsem write locked). */ struct llist_node cleanup_list; /* namespaces on death row */ @@ -95,8 +96,9 @@ struct net { /* core fib_rules */ struct list_head rules_ops; - struct list_head fib_notifier_ops; /* protected by net_sem */ - + struct list_head fib_notifier_ops; /* Populated by + * register_pernet_subsys() + */ struct net_device *loopback_dev; /* The loopback */ struct netns_core core; struct netns_mib mib; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index eef17ad29dea..9e8ee4640451 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -41,10 +41,10 @@ EXPORT_SYMBOL(init_net); static bool init_net_initialized; /* - * net_sem: protects: pernet_list, net_generic_ids, + * pernet_ops_rwsem: protects: pernet_list, net_generic_ids, * init_net_initialized and first_device pointer. */ -DECLARE_RWSEM(net_sem); +DECLARE_RWSEM(pernet_ops_rwsem); #define MIN_PERNET_OPS_ID \ ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *)) @@ -72,7 +72,7 @@ static int net_assign_generic(struct net *net, unsigned int id, void *data) BUG_ON(id < MIN_PERNET_OPS_ID); old_ng = rcu_dereference_protected(net->gen, - lockdep_is_held(&net_sem)); + lockdep_is_held(&pernet_ops_rwsem)); if (old_ng->s.len > id) { old_ng->ptr[id] = data; return 0; @@ -289,7 +289,7 @@ struct net *get_net_ns_by_id(struct net *net, int id) */ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) { - /* Must be called with net_sem held */ + /* Must be called with pernet_ops_rwsem held */ const struct pernet_operations *ops, *saved_ops; int error = 0; LIST_HEAD(net_exit_list); @@ -422,13 +422,13 @@ struct net *copy_net_ns(unsigned long flags, net->ucounts = ucounts; get_user_ns(user_ns); - rv = down_read_killable(&net_sem); + rv = down_read_killable(&pernet_ops_rwsem); if (rv < 0) goto put_userns; rv = setup_net(net, user_ns); - up_read(&net_sem); + up_read(&pernet_ops_rwsem); if (rv < 0) { put_userns: @@ -480,7 +480,7 @@ static void cleanup_net(struct work_struct *work) /* Atomically snapshot the list of namespaces to cleanup */ net_kill_list = llist_del_all(&cleanup_list); - down_read(&net_sem); + down_read(&pernet_ops_rwsem); /* Don't let anyone else find us. */ rtnl_lock(); @@ -519,7 +519,7 @@ static void cleanup_net(struct work_struct *work) list_for_each_entry_reverse(ops, &pernet_list, list) ops_free_list(ops, &net_exit_list); - up_read(&net_sem); + up_read(&pernet_ops_rwsem); /* Ensure there are no outstanding rcu callbacks using this * network namespace. @@ -546,8 +546,8 @@ static void cleanup_net(struct work_struct *work) */ void net_ns_barrier(void) { - down_write(&net_sem); - up_write(&net_sem); + down_write(&pernet_ops_rwsem); + up_write(&pernet_ops_rwsem); } EXPORT_SYMBOL(net_ns_barrier); @@ -869,12 +869,12 @@ static int __init net_ns_init(void) rcu_assign_pointer(init_net.gen, ng); - down_write(&net_sem); + down_write(&pernet_ops_rwsem); if (setup_net(&init_net, &init_user_ns)) panic("Could not setup the initial network namespace"); init_net_initialized = true; - up_write(&net_sem); + up_write(&pernet_ops_rwsem); register_pernet_subsys(&net_ns_ops); @@ -1013,9 +1013,9 @@ static void unregister_pernet_operations(struct pernet_operations *ops) int register_pernet_subsys(struct pernet_operations *ops) { int error; - down_write(&net_sem); + down_write(&pernet_ops_rwsem); error = register_pernet_operations(first_device, ops); - up_write(&net_sem); + up_write(&pernet_ops_rwsem); return error; } EXPORT_SYMBOL_GPL(register_pernet_subsys); @@ -1031,9 +1031,9 @@ EXPORT_SYMBOL_GPL(register_pernet_subsys); */ void unregister_pernet_subsys(struct pernet_operations *ops) { - down_write(&net_sem); + down_write(&pernet_ops_rwsem); unregister_pernet_operations(ops); - up_write(&net_sem); + up_write(&pernet_ops_rwsem); } EXPORT_SYMBOL_GPL(unregister_pernet_subsys); @@ -1059,11 +1059,11 @@ EXPORT_SYMBOL_GPL(unregister_pernet_subsys); int register_pernet_device(struct pernet_operations *ops) { int error; - down_write(&net_sem); + down_write(&pernet_ops_rwsem); error = register_pernet_operations(&pernet_list, ops); if (!error && (first_device == &pernet_list)) first_device = &ops->list; - up_write(&net_sem); + up_write(&pernet_ops_rwsem); return error; } EXPORT_SYMBOL_GPL(register_pernet_device); @@ -1079,11 +1079,11 @@ EXPORT_SYMBOL_GPL(register_pernet_device); */ void unregister_pernet_device(struct pernet_operations *ops) { - down_write(&net_sem); + down_write(&pernet_ops_rwsem); if (&ops->list == first_device) first_device = first_device->next; unregister_pernet_operations(ops); - up_write(&net_sem); + up_write(&pernet_ops_rwsem); } EXPORT_SYMBOL_GPL(unregister_pernet_device); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 31438b63d4b4..73011a60434c 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -460,11 +460,11 @@ static void rtnl_lock_unregistering_all(void) void rtnl_link_unregister(struct rtnl_link_ops *ops) { /* Close the race with cleanup_net() */ - down_write(&net_sem); + down_write(&pernet_ops_rwsem); rtnl_lock_unregistering_all(); __rtnl_link_unregister(ops); rtnl_unlock(); - up_write(&net_sem); + up_write(&pernet_ops_rwsem); } EXPORT_SYMBOL_GPL(rtnl_link_unregister); -- cgit v1.2.3 From 8518e9bb98b602eca0717d5aaad63ccbe56539d2 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Tue, 27 Mar 2018 18:02:32 +0300 Subject: 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(-) (limited to 'include') 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); -- cgit v1.2.3