[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/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index c58fa0d..122d55d 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -14,6 +14,7 @@
 #include <linux/skbuff.h>
 #include <linux/poll.h>
 #include <linux/proc_fs.h>
+#include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
@@ -829,8 +830,8 @@
 	}
 
 #ifdef CONFIG_PROC_FS
-	proc_net_fops_create("rxrpc_calls", 0, &rxrpc_call_seq_fops);
-	proc_net_fops_create("rxrpc_conns", 0, &rxrpc_connection_seq_fops);
+	proc_net_fops_create(&init_net, "rxrpc_calls", 0, &rxrpc_call_seq_fops);
+	proc_net_fops_create(&init_net, "rxrpc_conns", 0, &rxrpc_connection_seq_fops);
 #endif
 	return 0;
 
@@ -868,8 +869,8 @@
 
 	_debug("flush scheduled work");
 	flush_workqueue(rxrpc_workqueue);
-	proc_net_remove("rxrpc_conns");
-	proc_net_remove("rxrpc_calls");
+	proc_net_remove(&init_net, "rxrpc_conns");
+	proc_net_remove(&init_net, "rxrpc_calls");
 	destroy_workqueue(rxrpc_workqueue);
 	kmem_cache_destroy(rxrpc_call_jar);
 	_leave("");