rhashtable: Add parent argument to mutex_is_held

Currently mutex_is_held can only test locks in the that are global
since it takes no arguments.  This prevents rhashtable from being
used in places where locks are lock, e.g., per-namespace locks.

This patch adds a parent field to mutex_is_held and rhashtable_params
so that local locks can be used (and tested).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index c7654b6..4b4b53b 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -32,7 +32,7 @@
 #ifdef CONFIG_PROVE_LOCKING
 int lockdep_rht_mutex_is_held(const struct rhashtable *ht)
 {
-	return ht->p.mutex_is_held();
+	return ht->p.mutex_is_held(ht->p.parent);
 }
 EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
 #endif
@@ -618,7 +618,7 @@
 #define TEST_NEXPANDS	4
 
 #ifdef CONFIG_PROVE_LOCKING
-static int test_mutex_is_held(void)
+static int test_mutex_is_held(void *parent)
 {
 	return 1;
 }