[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/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c
index cc0ee93..1699d42 100644
--- a/drivers/net/hamradio/bpqether.c
+++ b/drivers/net/hamradio/bpqether.c
@@ -83,6 +83,7 @@
 
 #include <net/ip.h>
 #include <net/arp.h>
+#include <net/net_namespace.h>
 
 #include <linux/bpqether.h>
 
@@ -594,7 +595,7 @@
 static int __init bpq_init_driver(void)
 {
 #ifdef CONFIG_PROC_FS
-	if (!proc_net_fops_create("bpqether", S_IRUGO, &bpq_info_fops)) {
+	if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
 		printk(KERN_ERR
 			"bpq: cannot create /proc/net/bpqether entry.\n");
 		return -ENOENT;
@@ -618,7 +619,7 @@
 
 	unregister_netdevice_notifier(&bpq_dev_notifier);
 
-	proc_net_remove("bpqether");
+	proc_net_remove(&init_net, "bpqether");
 
 	rtnl_lock();
 	while (!list_empty(&bpq_devices)) {