[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/sched/sch_api.c b/net/sched/sch_api.c
index dee0d5f..efc383c 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -28,6 +28,7 @@
 #include <linux/list.h>
 #include <linux/hrtimer.h>
 
+#include <net/net_namespace.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 
@@ -1251,7 +1252,7 @@
 {
 	register_qdisc(&pfifo_qdisc_ops);
 	register_qdisc(&bfifo_qdisc_ops);
-	proc_net_fops_create("psched", 0, &psched_fops);
+	proc_net_fops_create(&init_net, "psched", 0, &psched_fops);
 
 	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL);
 	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL);