[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/wireless/wext.c b/net/wireless/wext.c
index debf519..b8069af 100644
--- a/net/wireless/wext.c
+++ b/net/wireless/wext.c
@@ -93,6 +93,7 @@
 #include <linux/if_arp.h>		/* ARPHRD_ETHER */
 #include <linux/etherdevice.h>		/* compare_ether_addr */
 #include <linux/interrupt.h>
+#include <net/net_namespace.h>
 
 #include <linux/wireless.h>		/* Pretty obvious */
 #include <net/iw_handler.h>		/* New driver API */
@@ -686,7 +687,7 @@
 int __init wext_proc_init(void)
 {
 	/* Create /proc/net/wireless entry */
-	if (!proc_net_fops_create("wireless", S_IRUGO, &wireless_seq_fops))
+	if (!proc_net_fops_create(&init_net, "wireless", S_IRUGO, &wireless_seq_fops))
 		return -ENOMEM;
 
 	return 0;