[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/isdn/hardware/eicon/diva_didd.c b/drivers/isdn/hardware/eicon/diva_didd.c
index d755d90..993b14c 100644
--- a/drivers/isdn/hardware/eicon/diva_didd.c
+++ b/drivers/isdn/hardware/eicon/diva_didd.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/proc_fs.h>
+#include <net/net_namespace.h>
 
 #include "platform.h"
 #include "di_defs.h"
@@ -86,7 +87,7 @@
 
 static int DIVA_INIT_FUNCTION create_proc(void)
 {
-	proc_net_eicon = proc_mkdir("net/eicon", NULL);
+	proc_net_eicon = proc_mkdir("eicon", init_net.proc_net);
 
 	if (proc_net_eicon) {
 		if ((proc_didd =
@@ -102,7 +103,7 @@
 static void remove_proc(void)
 {
 	remove_proc_entry(DRIVERLNAME, proc_net_eicon);
-	remove_proc_entry("net/eicon", NULL);
+	remove_proc_entry("eicon", init_net.proc_net);
 }
 
 static int DIVA_INIT_FUNCTION divadidd_init(void)