Split up unlink_thd in several functions

include/mysql/thread_pool_priv.h

@@ -94,8 +94,10 @@ bool thd_is_connection_alive(THD *thd);
 void close_connection(THD *thd, uint errcode);
 /* End the connection before closing it */
 void end_connection(THD *thd);
+/* Decrement connection counter */
+void dec_connection_count();
 /* Destroy THD object */
-void unlink_thd(THD *thd);
+void delete_thd(THD *thd);
 
 /*
   thread_created is maintained by thread pool when activated since

sql/mysqld.cc

@@ -2009,6 +2009,36 @@ extern "C" sig_handler end_thread_signal(int sig __attribute__((unused)))
 }
 
 
+/*
+  Decrease number of connections
+
+  SYNOPSIS
+    dec_connection_count()
+*/
+
+void dec_connection_count()
+{
+  mysql_mutex_lock(&LOCK_connection_count);
+  --connection_count;
+  mysql_mutex_unlock(&LOCK_connection_count);
+}
+
+
+/*
+  Delete the THD object and decrease number of threads
+
+  SYNOPSIS
+    delete_thd()
+    thd		 Thread handler
+*/
+
+void delete_thd(THD *thd)
+{
+  thread_count--;
+  delete thd;
+}
+
+
 /*
   Unlink thd from global list of available connections and free thd
 
@@ -2024,15 +2054,10 @@ void unlink_thd(THD *thd)
 {
   DBUG_ENTER("unlink_thd");
   DBUG_PRINT("enter", ("thd: 0x%lx", (long) thd));
-  thd->cleanup();
-
-  mysql_mutex_lock(&LOCK_connection_count);
-  --connection_count;
-  mysql_mutex_unlock(&LOCK_connection_count);
 
+  dec_connection_count();
   mysql_mutex_lock(&LOCK_thread_count);
-  thread_count--;
-  delete thd;
+  delete_thd(thd);
   DBUG_VOID_RETURN;
 }