rhashtable: Move mutex_is_held under PROVE_LOCKING

The rhashtable function mutex_is_held is only used when PROVE_LOCKING
is enabled.  This patch makes the mutex_is_held field in rhashtable
optional depending on PROVE_LOCKING.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/rhashtable.h

@@ -65,7 +65,9 @@ struct rhashtable_params {
 						 size_t new_size);
 	bool			(*shrink_decision)(const struct rhashtable *ht,
 						   size_t new_size);
+#ifdef CONFIG_PROVE_LOCKING
 	int			(*mutex_is_held)(void);
+#endif
 };
 
 /**

lib/rhashtable.c

@@ -532,7 +532,9 @@ static size_t rounded_hashtable_size(struct rhashtable_params *params)
  *	.key_offset = offsetof(struct test_obj, key),
  *	.key_len = sizeof(int),
  *	.hashfn = arch_fast_hash,
+ * #ifdef CONFIG_PROVE_LOCKING
  *	.mutex_is_held = &my_mutex_is_held,
+ * #endif
  * };
  *
  * Configuration Example 2: Variable length keys
@@ -552,7 +554,9 @@ static size_t rounded_hashtable_size(struct rhashtable_params *params)
  *	.head_offset = offsetof(struct test_obj, node),
  *	.hashfn = arch_fast_hash,
  *	.obj_hashfn = my_hash_fn,
+ * #ifdef CONFIG_PROVE_LOCKING
  *	.mutex_is_held = &my_mutex_is_held,
+ * #endif
  * };
  */
 int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
@@ -613,10 +617,12 @@ EXPORT_SYMBOL_GPL(rhashtable_destroy);
 #define TEST_PTR	((void *) 0xdeadbeef)
 #define TEST_NEXPANDS	4
 
+#ifdef CONFIG_PROVE_LOCKING
 static int test_mutex_is_held(void)
 {
 	return 1;
 }
+#endif
 
 struct test_obj {
 	void			*ptr;
@@ -767,7 +773,9 @@ static int __init test_rht_init(void)
 		.key_offset = offsetof(struct test_obj, value),
 		.key_len = sizeof(int),
 		.hashfn = arch_fast_hash,
+#ifdef CONFIG_PROVE_LOCKING
 		.mutex_is_held = &test_mutex_is_held,
+#endif
 		.grow_decision = rht_grow_above_75,
 		.shrink_decision = rht_shrink_below_30,
 	};