Merge 10.3 into 10.4

storage/innobase/include/dict0mem.h

@@ -2110,7 +2110,8 @@ public:
 	UT_LIST_BASE_NODE_T(dict_index_t)	indexes;
 #ifdef BTR_CUR_HASH_ADAPT
 	/** List of detached indexes that are waiting to be freed along with
-	the last adaptive hash index entry */
+	the last adaptive hash index entry.
+	Protected by autoinc_mutex (sic!) */
 	UT_LIST_BASE_NODE_T(dict_index_t)	freed_indexes;
 #endif /* BTR_CUR_HASH_ADAPT */
 
@@ -2277,7 +2278,7 @@ public:
 	from a select. */
 	lock_t*					autoinc_lock;
 
-	/** Mutex protecting the autoincrement counter. */
+	/** Mutex protecting the autoinc counter and freed_indexes. */
 	std::mutex				autoinc_mutex;
 
 	/** Autoinc counter value to give to the next inserted row. */
@@ -2309,7 +2310,6 @@ public:
 	determine whether we can evict the table from the dictionary cache.
 	It is protected by lock_sys.mutex. */
 	ulint					n_rec_locks;
-
 private:
 	/** 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