diff options
| -rw-r--r-- | include/net/net_namespace.h | 6 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 30 |
2 files changed, 26 insertions, 10 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index f306b2aa15a4..9158ec1ad06f 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -313,6 +313,12 @@ 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 synchronization via net_mutex. + */ + bool async; }; /* diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index f8453c438798..2a01ff32d9c7 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -29,6 +29,7 @@ static LIST_HEAD(pernet_list); static struct list_head *first_device = &pernet_list; +/* Used only if there are !async pernet_operations registered */ DEFINE_MUTEX(net_mutex); LIST_HEAD(net_namespace_list); @@ -41,8 +42,9 @@ struct net init_net = { EXPORT_SYMBOL(init_net); static bool init_net_initialized; +static unsigned nr_sync_pernet_ops; /* - * net_sem: protects: pernet_list, net_generic_ids, + * net_sem: protects: pernet_list, net_generic_ids, nr_sync_pernet_ops, * init_net_initialized and first_device pointer. */ DECLARE_RWSEM(net_sem); @@ -70,11 +72,10 @@ static int net_assign_generic(struct net *net, unsigned int id, void *data) { struct net_generic *ng, *old_ng; - BUG_ON(!mutex_is_locked(&net_mutex)); BUG_ON(id < MIN_PERNET_OPS_ID); old_ng = rcu_dereference_protected(net->gen, - lockdep_is_held(&net_mutex)); + lockdep_is_held(&net_sem)); if (old_ng->s.len > id) { old_ng->ptr[id] = data; return 0; @@ -426,11 +427,14 @@ struct net *copy_net_ns(unsigned long flags, rv = down_read_killable(&net_sem); if (rv < 0) goto put_userns; - rv = mutex_lock_killable(&net_mutex); - if (rv < 0) - goto up_read; + if (nr_sync_pernet_ops) { + rv = mutex_lock_killable(&net_mutex); + if (rv < 0) + goto up_read; + } rv = setup_net(net, user_ns); - mutex_unlock(&net_mutex); + if (nr_sync_pernet_ops) + mutex_unlock(&net_mutex); up_read: up_read(&net_sem); if (rv < 0) { @@ -487,7 +491,8 @@ static void cleanup_net(struct work_struct *work) spin_unlock_irq(&cleanup_list_lock); down_read(&net_sem); - mutex_lock(&net_mutex); + if (nr_sync_pernet_ops) + mutex_lock(&net_mutex); /* Don't let anyone else find us. */ rtnl_lock(); @@ -522,7 +527,8 @@ static void cleanup_net(struct work_struct *work) list_for_each_entry_reverse(ops, &pernet_list, list) ops_exit_list(ops, &net_exit_list); - mutex_unlock(&net_mutex); + if (nr_sync_pernet_ops) + mutex_unlock(&net_mutex); /* Free the net generic variables */ list_for_each_entry_reverse(ops, &pernet_list, list) @@ -994,6 +1000,9 @@ again: rcu_barrier(); if (ops->id) ida_remove(&net_generic_ids, *ops->id); + } else if (!ops->async) { + pr_info_once("Pernet operations %ps are sync.\n", ops); + nr_sync_pernet_ops++; } return error; @@ -1001,7 +1010,8 @@ again: static void unregister_pernet_operations(struct pernet_operations *ops) { - + if (!ops->async) + BUG_ON(nr_sync_pernet_ops-- == 0); __unregister_pernet_operations(ops); rcu_barrier(); if (ops->id) |