MDEV-17441 - InnoDB transition to C++11 atomics

Added lf_hash_size() macro, so that callers don't need to use atomic
operations.

include/lf.h

@@ -167,6 +167,8 @@ void *lf_hash_search_using_hash_value(LF_HASH *hash, LF_PINS *pins,
 int lf_hash_delete(LF_HASH *hash, LF_PINS *pins, const void *key, uint keylen);
 int lf_hash_iterate(LF_HASH *hash, LF_PINS *pins,
                     my_hash_walk_action action, void *argument);
+#define lf_hash_size(hash) \
+  my_atomic_load32_explicit(&(hash)->count, MY_MEMORY_ORDER_RELAXED)
 /*
   shortcut macros to access underlying pinbox functions from an LF_HASH
   see lf_pinbox_get_pins() and lf_pinbox_put_pins()

sql/mdl.cc

@@ -782,7 +782,7 @@ void MDL_map::destroy()
 {
   delete m_backup_lock;
 
-  DBUG_ASSERT(!my_atomic_load32(&m_locks.count));
+  DBUG_ASSERT(!lf_hash_size(&m_locks));
   lf_hash_destroy(&m_locks);
 }
 

sql/table_cache.cc

@@ -689,7 +689,7 @@ void tdc_deinit(void)
 
 ulong tdc_records(void)
 {
-  return my_atomic_load32_explicit(&tdc_hash.count, MY_MEMORY_ORDER_RELAXED);
+  return lf_hash_size(&tdc_hash);
 }
 
 

storage/innobase/include/trx0sys.h

@@ -704,11 +704,7 @@ class rw_trx_hash_t
     because it may change even before this method returns.
   */
 
-  uint32_t size()
-  {
-    return uint32_t(my_atomic_load32_explicit(&hash.count,
-					      MY_MEMORY_ORDER_RELAXED));
-  }
+  uint32_t size() { return uint32_t(lf_hash_size(&hash)); }
 
 
   /**