From a685e08987d1edf1995b76511d4c98ea0e905377 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 8 Jun 2011 21:13:01 -0400 Subject: Delay struct net freeing while there's a sysfs instance refering to it * new refcount in struct net, controlling actual freeing of the memory * new method in kobj_ns_type_operations (->drop_ns()) * ->current_ns() semantics change - it's supposed to be followed by corresponding ->drop_ns(). For struct net in case of CONFIG_NET_NS it bumps the new refcount; net_drop_ns() decrements it and calls net_free() if the last reference has been dropped. Method renamed to ->grab_current_ns(). * old net_free() callers call net_drop_ns() instead. * sysfs_exit_ns() is gone, along with a large part of callchain leading to it; now that the references stored in ->ns[...] stay valid we do not need to hunt them down and replace them with NULL. That fixes problems in sysfs_lookup() and sysfs_readdir(), along with getting rid of sb->s_instances abuse. Note that struct net *shutdown* logics has not changed - net_cleanup() is called exactly when it used to be called. The only thing postponed by having a sysfs instance refering to that struct net is actual freeing of memory occupied by struct net. Signed-off-by: Al Viro --- include/net/net_namespace.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'include/net/net_namespace.h') diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 2bf9ed9ef26b..aef430d779bd 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -35,8 +35,11 @@ struct netns_ipvs; #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS) struct net { + atomic_t passive; /* To decided when the network + * namespace should be freed. + */ atomic_t count; /* To decided when the network - * namespace should be freed. + * namespace should be shut down. */ #ifdef NETNS_REFCNT_DEBUG atomic_t use_count; /* To track references we @@ -154,6 +157,9 @@ int net_eq(const struct net *net1, const struct net *net2) { return net1 == net2; } + +extern void net_drop_ns(void *); + #else static inline struct net *get_net(struct net *net) @@ -175,6 +181,8 @@ int net_eq(const struct net *net1, const struct net *net2) { return 1; } + +#define net_drop_ns NULL #endif -- cgit v1.2.3