diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2007-09-26 22:40:08 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-10-10 16:52:55 -0700 |
| commit | f4618d39a34dab316090263b42cd8799f31ce277 (patch) | |
| tree | 75db202b492da1797145fde455b0c4c89cf41767 /net | |
| parent | 32db927686f6d475fc05b6229f82ed576c0c8096 (diff) | |
[NETNS]: Simplify the network namespace list locking rules.
Denis V. Lunev <den@sw.ru> noticed that the locking rules
for the network namespace list are over complicated and broken.
In particular the current register_netdev_notifier currently
does not take any lock making the for_each_net iteration racy
with network namespace creation and destruction. Oops.
The fact that we need to use for_each_net in rtnl_unlock() when
the rtnetlink support becomes per network namespace makes designing
the proper locking tricky. In addition we need to be able to call
rtnl_lock() and rtnl_unlock() when we have the net_mutex held.
After thinking about it and looking at the alternatives carefully
it looks like the simplest and most maintainable solution is
to remove net_list_mutex altogether, and to use the rtnl_mutex instead.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/net_namespace.c | 23 |
1 files changed, 6 insertions, 17 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index e478e353ea6..0e0ca6d06fa 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -15,7 +15,6 @@ static LIST_HEAD(pernet_list); static struct list_head *first_device = &pernet_list; static DEFINE_MUTEX(net_mutex); -static DEFINE_MUTEX(net_list_mutex); LIST_HEAD(net_namespace_list); static struct kmem_cache *net_cachep; @@ -23,16 +22,6 @@ static struct kmem_cache *net_cachep; struct net init_net; EXPORT_SYMBOL_GPL(init_net); -void net_lock(void) -{ - mutex_lock(&net_list_mutex); -} - -void net_unlock(void) -{ - mutex_unlock(&net_list_mutex); -} - static struct net *net_alloc(void) { return kmem_cache_alloc(net_cachep, GFP_KERNEL); @@ -62,9 +51,9 @@ static void cleanup_net(struct work_struct *work) mutex_lock(&net_mutex); /* Don't let anyone else find us. */ - net_lock(); + rtnl_lock(); list_del(&net->list); - net_unlock(); + rtnl_unlock(); /* Run all of the network namespace exit methods */ list_for_each_entry_reverse(ops, &pernet_list, list) { @@ -151,9 +140,9 @@ struct net *copy_net_ns(unsigned long flags, struct net *old_net) if (err) goto out_unlock; - net_lock(); + rtnl_lock(); list_add_tail(&new_net->list, &net_namespace_list); - net_unlock(); + rtnl_unlock(); out_unlock: @@ -178,9 +167,9 @@ static int __init net_ns_init(void) mutex_lock(&net_mutex); err = setup_net(&init_net); - net_lock(); + rtnl_lock(); list_add_tail(&init_net.list, &net_namespace_list); - net_unlock(); + rtnl_unlock(); mutex_unlock(&net_mutex); if (err) |