[NETNS]: Make netns refconting debug like a socket one.

Make release_net/hold_net noop for performance-hungry people. This is a debug
staff and should be used in the debug mode only.

Add check for net != NULL in hold/release calls. This will be required
later on.

[ Added minor simplifications suggested by Brian Haley. -DaveM ]

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 763674e1e593..72b4c184dd84 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -35,7 +35,9 @@ static __net_init int setup_net(struct net *net)
         struct net_generic *ng;
 
         atomic_set(&net->count, 1);
+#ifdef NETNS_REFCNT_DEBUG
         atomic_set(&net->use_count, 0);
+#endif
 
         error = -ENOMEM;
         ng = kzalloc(sizeof(struct net_generic) +
@@ -86,11 +88,13 @@ static void net_free(struct net *net)
         if (!net)
                 return;
 
+#ifdef NETNS_REFCNT_DEBUG
         if (unlikely(atomic_read(&net->use_count) != 0)) {
                 printk(KERN_EMERG "network namespace not free! Usage: %d\n",
                         atomic_read(&net->use_count));
                 return;
         }
+#endif
 
         kmem_cache_free(net_cachep, net);
 }