[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/ipvs/ip_vs_app.c b/net/ipv4/ipvs/ip_vs_app.c
index 8d6901d..341474e 100644
--- a/net/ipv4/ipvs/ip_vs_app.c
+++ b/net/ipv4/ipvs/ip_vs_app.c
@@ -25,6 +25,7 @@
 #include <linux/skbuff.h>
 #include <linux/in.h>
 #include <linux/ip.h>
+#include <net/net_namespace.h>
 #include <net/protocol.h>
 #include <net/tcp.h>
 #include <asm/system.h>
@@ -616,12 +617,12 @@
 int ip_vs_app_init(void)
 {
 	/* we will replace it with proc_net_ipvs_create() soon */
-	proc_net_fops_create("ip_vs_app", 0, &ip_vs_app_fops);
+	proc_net_fops_create(&init_net, "ip_vs_app", 0, &ip_vs_app_fops);
 	return 0;
 }
 
 
 void ip_vs_app_cleanup(void)
 {
-	proc_net_remove("ip_vs_app");
+	proc_net_remove(&init_net, "ip_vs_app");
 }