[NET]: Make /proc/net per network namespace

This patch makes /proc/net per network namespace.  It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.

Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index dc927329..15c8a92 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -27,6 +27,7 @@
 #include <linux/netdevice.h>
 #include <linux/if_arp.h>
 #include <linux/skbuff.h>
+#include <net/net_namespace.h>
 #include <net/sock.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -1447,9 +1448,9 @@
 
 	nr_loopback_init();
 
-	proc_net_fops_create("nr", S_IRUGO, &nr_info_fops);
-	proc_net_fops_create("nr_neigh", S_IRUGO, &nr_neigh_fops);
-	proc_net_fops_create("nr_nodes", S_IRUGO, &nr_nodes_fops);
+	proc_net_fops_create(&init_net, "nr", S_IRUGO, &nr_info_fops);
+	proc_net_fops_create(&init_net, "nr_neigh", S_IRUGO, &nr_neigh_fops);
+	proc_net_fops_create(&init_net, "nr_nodes", S_IRUGO, &nr_nodes_fops);
 out:
 	return rc;
 fail:
@@ -1477,9 +1478,9 @@
 {
 	int i;
 
-	proc_net_remove("nr");
-	proc_net_remove("nr_neigh");
-	proc_net_remove("nr_nodes");
+	proc_net_remove(&init_net, "nr");
+	proc_net_remove(&init_net, "nr_neigh");
+	proc_net_remove(&init_net, "nr_nodes");
 	nr_loopback_clear();
 
 	nr_rt_free();