[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/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 7003cc1..35683e1 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -49,6 +49,7 @@
 #include <linux/mroute.h>
 #include <linux/init.h>
 #include <linux/if_ether.h>
+#include <net/net_namespace.h>
 #include <net/ip.h>
 #include <net/protocol.h>
 #include <linux/skbuff.h>
@@ -1922,7 +1923,7 @@
 	ipmr_expire_timer.function=ipmr_expire_process;
 	register_netdevice_notifier(&ip_mr_notifier);
 #ifdef CONFIG_PROC_FS
-	proc_net_fops_create("ip_mr_vif", 0, &ipmr_vif_fops);
-	proc_net_fops_create("ip_mr_cache", 0, &ipmr_mfc_fops);
+	proc_net_fops_create(&init_net, "ip_mr_vif", 0, &ipmr_vif_fops);
+	proc_net_fops_create(&init_net, "ip_mr_cache", 0, &ipmr_mfc_fops);
 #endif
 }