kernel: make taskstats available from all net namespaces

If getdelays runs in a non-init network namespace, it will fail in getting
delayacct stats even if it has privilege of root user, which seems to be
not very reasonable.  We can simply reproduce this by executing commands:

	unshare -n
	getdelays -d -p <pid>

I don't think net namespace should be an obstacle to the normal execution
of getdelay function.  So let's make it available from all net namespaces.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: xu xin <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Yang Yang <[email protected]>
Cc: "Dr. Thomas Orgis" <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: Ismael Luceno <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: xu xin

kernel/taskstats.c

@@ -688,6 +688,7 @@ static struct genl_family family __ro_after_init = {
 	.module		= THIS_MODULE,
 	.ops		= taskstats_ops,
 	.n_ops		= ARRAY_SIZE(taskstats_ops),
+	.netnsok	= true,
 };
 
 /* Needed early in initialization */