rhashtable: don't allocate ht structure on stack in test_rht_init

With object runtime debugging enabled, the rhashtable test suite
will rightfully throw a warning "ODEBUG: object is on stack, but
not annotated" from rhashtable_init().

This is because run_work is (correctly) being initialized via
INIT_WORK(), and not annotated by INIT_WORK_ONSTACK(). Meaning,
rhashtable_init() is okay as is, we just need to move ht e.g.,
into global scope.

It never triggered anything, since test_rhashtable is rather a
controlled environment and effectively runs to completion, so
that stack memory is not vanishing underneath us, we shouldn't
confuse any testers with it though.

Fixes: 7e1e7763 ("lib: Resizable, Scalable, Concurrent Hash Table")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

lib/test_rhashtable.c

@@ -191,9 +191,10 @@ static int __init test_rhashtable(struct rhashtable *ht)
 	return err;
 }
 
+static struct rhashtable ht;
+
 static int __init test_rht_init(void)
 {
-	struct rhashtable ht;
 	struct rhashtable_params params = {
 		.nelem_hint = TEST_HT_SIZE,
 		.head_offset = offsetof(struct test_obj, node),