galera fixes related to THD::LOCK_thd_kill

Since 2017 (c2118a08) THD::awake() no longer requires LOCK_thd_data.
It uses LOCK_thd_kill, and this latter mutex is used to prevent
a thread of dying, not LOCK_thd_data as before.

include/mysql/service_wsrep.h

@@ -119,6 +119,8 @@ extern struct wsrep_service_st {
   my_bool                     (*wsrep_thd_is_applier_func)(MYSQL_THD);
   void                        (*wsrep_report_bf_lock_wait_func)(MYSQL_THD thd,
                                                                 unsigned long long trx_id);
+  void                        (*wsrep_thd_kill_LOCK_func)(THD *thd);
+  void                        (*wsrep_thd_kill_UNLOCK_func)(THD *thd);
 } *wsrep_service;
 
 #ifdef MYSQL_DYNAMIC_PLUGIN
@@ -143,6 +145,8 @@ extern struct wsrep_service_st {
 #define wsrep_run_wsrep_commit(T,A) wsrep_service->wsrep_run_wsrep_commit_func(T,A)
 #define wsrep_thd_LOCK(T) wsrep_service->wsrep_thd_LOCK_func(T)
 #define wsrep_thd_UNLOCK(T) wsrep_service->wsrep_thd_UNLOCK_func(T)
+#define wsrep_thd_kill_LOCK(T) wsrep_service->wsrep_thd_kill_LOCK_func(T)
+#define wsrep_thd_kill_UNLOCK(T) wsrep_service->wsrep_thd_kill_UNLOCK_func(T)
 #define wsrep_thd_awake(T,S) wsrep_service->wsrep_thd_awake_func(T,S)
 #define wsrep_thd_conflict_state(T,S) wsrep_service->wsrep_thd_conflict_state_func(T,S)
 #define wsrep_thd_conflict_state_str(T) wsrep_service->wsrep_thd_conflict_state_str_func(T)
@@ -226,6 +230,8 @@ void wsrep_lock_rollback();
 void wsrep_post_commit(THD* thd, bool all);
 void wsrep_thd_LOCK(THD *thd);
 void wsrep_thd_UNLOCK(THD *thd);
+void wsrep_thd_kill_LOCK(THD *thd);
+void wsrep_thd_kill_UNLOCK(THD *thd);
 void wsrep_thd_awake(THD *thd, my_bool signal);
 void wsrep_thd_set_conflict_state(THD *thd, enum wsrep_conflict_state state);
 bool wsrep_thd_ignore_table(THD *thd);

include/service_versions.h

@@ -41,4 +41,4 @@
 #define VERSION_thd_specifics           0x0100
 #define VERSION_thd_timezone            0x0100
 #define VERSION_thd_wait                0x0100
-#define VERSION_wsrep                   0x0202
+#define VERSION_wsrep                   0x0203

sql/sql_plugin_services.ic

@@ -187,7 +187,9 @@ static struct wsrep_service_st wsrep_handler = {
   wsrep_unlock_rollback,
   wsrep_set_data_home_dir,
   wsrep_thd_is_applier,
-  wsrep_report_bf_lock_wait
+  wsrep_report_bf_lock_wait,
+  wsrep_thd_kill_LOCK,
+  wsrep_thd_kill_UNLOCK
 };
 
 static struct thd_specifics_service_st thd_specifics_handler=

sql/wsrep_mysqld.cc

@@ -2383,12 +2383,7 @@ void wsrep_close_client_connections(my_bool wait_to_end, THD *except_caller_thd)
     /*
       instead of wsrep_close_thread() we do now  soft kill by THD::awake
      */
-    mysql_mutex_lock(&tmp->LOCK_thd_data);
-
     tmp->awake(KILL_CONNECTION);
-
-    mysql_mutex_unlock(&tmp->LOCK_thd_data);
-
   }
   mysql_mutex_unlock(&LOCK_thread_count);
 
@@ -2676,6 +2671,18 @@ void wsrep_thd_UNLOCK(THD *thd)
 }
 
 
+void wsrep_thd_kill_LOCK(THD *thd)
+{
+  mysql_mutex_lock(&thd->LOCK_thd_kill);
+}
+
+
+void wsrep_thd_kill_UNLOCK(THD *thd)
+{
+  mysql_mutex_unlock(&thd->LOCK_thd_kill);
+}
+
+
 extern "C" time_t wsrep_thd_query_start(THD *thd) 
 {
   return thd->query_start();