[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/wireless/strip.c b/drivers/net/wireless/strip.c
index ef32a5c..edb214e 100644
--- a/drivers/net/wireless/strip.c
+++ b/drivers/net/wireless/strip.c
@@ -107,6 +107,7 @@
 #include <linux/serialP.h>
 #include <linux/rcupdate.h>
 #include <net/arp.h>
+#include <net/net_namespace.h>
 
 #include <linux/ip.h>
 #include <linux/tcp.h>
@@ -2787,7 +2788,7 @@
 	/*
 	 * Register the status file with /proc
 	 */
-	proc_net_fops_create("strip", S_IFREG | S_IRUGO, &strip_seq_fops);
+	proc_net_fops_create(&init_net, "strip", S_IFREG | S_IRUGO, &strip_seq_fops);
 
 	return status;
 }
@@ -2809,7 +2810,7 @@
 	}
 
 	/* Unregister with the /proc/net file here. */
-	proc_net_remove("strip");
+	proc_net_remove(&init_net, "strip");
 
 	if ((i = tty_unregister_ldisc(N_STRIP)))
 		printk(KERN_ERR "STRIP: can't unregister line discipline (err = %d)\n", i);