[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/hamradio/yam.c b/drivers/net/hamradio/yam.c
index 467559d..401724d 100644
--- a/drivers/net/hamradio/yam.c
+++ b/drivers/net/hamradio/yam.c
@@ -65,6 +65,7 @@
 #include <linux/kernel.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <net/net_namespace.h>
 
 #include <asm/uaccess.h>
 #include <linux/init.h>
@@ -1142,7 +1143,7 @@
 	yam_timer.expires = jiffies + HZ / 100;
 	add_timer(&yam_timer);
 
-	proc_net_fops_create("yam", S_IRUGO, &yam_info_fops);
+	proc_net_fops_create(&init_net, "yam", S_IRUGO, &yam_info_fops);
 	return 0;
  error:
 	while (--i >= 0) {
@@ -1174,7 +1175,7 @@
 		kfree(p);
 	}
 
-	proc_net_remove("yam");
+	proc_net_remove(&init_net, "yam");
 }
 
 /* --------------------------------------------------------------------- */