[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>
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index f880b0f..aa540e6 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -26,9 +26,11 @@
atomic_t count; /* To decided when the network
* namespace should be freed.
*/
+#ifdef NETNS_REFCNT_DEBUG
atomic_t use_count; /* To track references we
* destroy on demand
*/
+#endif
struct list_head list; /* list of network namespaces */
struct work_struct work; /* work struct for freeing */
@@ -117,17 +119,6 @@
__put_net(net);
}
-static inline struct net *hold_net(struct net *net)
-{
- atomic_inc(&net->use_count);
- return net;
-}
-
-static inline void release_net(struct net *net)
-{
- atomic_dec(&net->use_count);
-}
-
static inline
int net_eq(const struct net *net1, const struct net *net2)
{
@@ -143,15 +134,6 @@
{
}
-static inline struct net *hold_net(struct net *net)
-{
- return net;
-}
-
-static inline void release_net(struct net *net)
-{
-}
-
static inline struct net *maybe_get_net(struct net *net)
{
return net;
@@ -164,6 +146,32 @@
}
#endif
+
+#ifdef NETNS_REFCNT_DEBUG
+static inline struct net *hold_net(struct net *net)
+{
+ if (net)
+ atomic_inc(&net->use_count);
+ return net;
+}
+
+static inline void release_net(struct net *net)
+{
+ if (net)
+ atomic_dec(&net->use_count);
+}
+#else
+static inline struct net *hold_net(struct net *net)
+{
+ return net;
+}
+
+static inline void release_net(struct net *net)
+{
+}
+#endif
+
+
#define for_each_net(VAR) \
list_for_each_entry(VAR, &net_namespace_list, list)
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 763674e..72b4c18 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -35,7 +35,9 @@
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 @@
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);
}