net: make namespace iteration possible under RCU

All we need to take care of is using proper RCU list
add/del primitives and inserting a synchronize_rcu()
at one place to make sure the exit notifiers are run
after everybody has stopped iterating the list.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index ded434b032a4..b34a6ee73754 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -208,6 +208,9 @@ static inline struct net *read_pnet(struct net * const *pnet)
 #define for_each_net(VAR)                               \
         list_for_each_entry(VAR, &net_namespace_list, list)
 
+#define for_each_net_rcu(VAR)                           \
+        list_for_each_entry_rcu(VAR, &net_namespace_list, list)
+
 #ifdef CONFIG_NET_NS
 #define __net_init
 #define __net_exit