What does it mean to release a resource with children? Should the children

become children of the released resource's parent?  Should they be released
too?  Should we fail the release?

I bet we have no callers who expect this right now, but with
insert_resource() we may get some.  At the point where someone hits this
BUG we can figure out what semantics we want.
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/resource.c

@@ -181,6 +181,8 @@ static int __release_resource(struct resource *old)
 		}
 	}
 
+	WARN_ON(old->child);
+
 	p = &old->parent->child;
 	for (;;) {
 		tmp = *p;