Merge tag 'irqchip-4.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

Merge the first drop of irqchip updates for 4.9 from Marc Zyngier:

- ACPI IORT core code
- IORT support for the GICv3 ITS
- A few of GIC cleanups

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 9bafc211930c..68f594212759 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -938,6 +938,20 @@ bool userns_may_setgroups(const struct user_namespace *ns)
 	return allowed;
 }
 
+/*
+ * Returns true if @ns is the same namespace as or a descendant of
+ * @target_ns.
+ */
+bool current_in_userns(const struct user_namespace *target_ns)
+{
+	struct user_namespace *ns;
+	for (ns = current_user_ns(); ns; ns = ns->parent) {
+		if (ns == target_ns)
+			return true;
+	}
+	return false;
+}
+
 static inline struct user_namespace *to_user_ns(struct ns_common *ns)
 {
 	return container_of(ns, struct user_namespace, ns);