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author | Al Viro <viro@zeniv.linux.org.uk> | 2011-06-09 05:13:01 +0400 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-06-13 01:45:41 +0400 |
commit | a685e08987d1edf1995b76511d4c98ea0e905377 (patch) | |
tree | 1d42593e2bc320f8d93b98851b2df0fd432e3859 /include | |
parent | dde194a64bb5c3fd05d965775dc92e8a4920a53a (diff) | |
download | linux-a685e08987d1edf1995b76511d4c98ea0e905377.tar.xz |
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 <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/kobject_ns.h | 10 | ||||
-rw-r--r-- | include/linux/sysfs.h | 7 | ||||
-rw-r--r-- | include/net/net_namespace.h | 10 |
3 files changed, 15 insertions, 12 deletions
diff --git a/include/linux/kobject_ns.h b/include/linux/kobject_ns.h index 82cb5bf461fb..f66b065a8b5f 100644 --- a/include/linux/kobject_ns.h +++ b/include/linux/kobject_ns.h @@ -32,15 +32,17 @@ enum kobj_ns_type { /* * Callbacks so sysfs can determine namespaces - * @current_ns: return calling task's namespace + * @grab_current_ns: return a new reference to calling task's namespace * @netlink_ns: return namespace to which a sock belongs (right?) * @initial_ns: return the initial namespace (i.e. init_net_ns) + * @drop_ns: drops a reference to namespace */ struct kobj_ns_type_operations { enum kobj_ns_type type; - const void *(*current_ns)(void); + void *(*grab_current_ns)(void); const void *(*netlink_ns)(struct sock *sk); const void *(*initial_ns)(void); + void (*drop_ns)(void *); }; int kobj_ns_type_register(const struct kobj_ns_type_operations *ops); @@ -48,9 +50,9 @@ int kobj_ns_type_registered(enum kobj_ns_type type); const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent); const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj); -const void *kobj_ns_current(enum kobj_ns_type type); +void *kobj_ns_grab_current(enum kobj_ns_type type); const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk); const void *kobj_ns_initial(enum kobj_ns_type type); -void kobj_ns_exit(enum kobj_ns_type type, const void *ns); +void kobj_ns_drop(enum kobj_ns_type type, void *ns); #endif /* _LINUX_KOBJECT_NS_H */ diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index c3acda60eee0..e2696d76a599 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -177,9 +177,6 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd); void sysfs_put(struct sysfs_dirent *sd); -/* Called to clear a ns tag when it is no longer valid */ -void sysfs_exit_ns(enum kobj_ns_type type, const void *tag); - int __must_check sysfs_init(void); #else /* CONFIG_SYSFS */ @@ -338,10 +335,6 @@ static inline void sysfs_put(struct sysfs_dirent *sd) { } -static inline void sysfs_exit_ns(int type, const void *tag) -{ -} - static inline int __must_check sysfs_init(void) { return 0; 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 |