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

dict_table_t::n_ref_count transition to Atomic_counter.

storage/innobase/dict/dict0dict.cc

@@ -437,7 +437,7 @@ dict_table_try_drop_aborted(
 	dict_table_t*	table,		/*!< in: table, or NULL if it
 					needs to be looked up again */
 	table_id_t	table_id,	/*!< in: table identifier */
-	int32		ref_count)	/*!< in: expected table->n_ref_count */
+	uint32_t	ref_count)	/*!< in: expected table->n_ref_count */
 {
 	trx_t*		trx;
 

storage/innobase/include/dict0dict.ic

@@ -1281,7 +1281,7 @@ void
 dict_table_t::acquire()
 {
 	ut_ad(mutex_own(&dict_sys->mutex));
-	my_atomic_add32_explicit(&n_ref_count, 1, MY_MEMORY_ORDER_RELAXED);
+	n_ref_count++;
 }
 
 /** Release the table handle.
@@ -1290,8 +1290,7 @@ inline
 bool
 dict_table_t::release()
 {
-	int32 n = my_atomic_add32_explicit(
-			&n_ref_count, -1, MY_MEMORY_ORDER_RELAXED);
+	auto n = n_ref_count--;
 	ut_ad(n > 0);
 	return n == 1;
 }

storage/innobase/include/dict0mem.h

@@ -1615,11 +1615,7 @@ struct dict_table_t {
 
 	/** Get reference count.
 	@return current value of n_ref_count */
-	inline int32 get_ref_count()
-	{
-		return my_atomic_load32_explicit(&n_ref_count,
-						 MY_MEMORY_ORDER_RELAXED);
-	}
+	inline uint32_t get_ref_count() const { return n_ref_count; }
 
 	/** Acquire the table handle. */
 	inline void acquire();
@@ -2139,7 +2135,7 @@ struct dict_table_t {
 	/** Count of how many handles are opened to this table. Dropping of the
 	table is NOT allowed until this count gets to zero. MySQL does NOT
 	itself check the number of open handles at DROP. */
-	int32					n_ref_count;
+	Atomic_counter<uint32_t>		n_ref_count;
 
 public:
 	/** List of locks on the table. Protected by lock_sys.mutex. */