bugfix: federated/replication did not increment bytes_received status variable

because mysql->net.thd was reset to NULL in mysql_real_connect()
and thd_increment_bytes_received() didn't do anything.

Fix:
* set mysql->net.thd to current_thd instread.
* remove the test for non-null THD from a very often used
  function thd_increment_bytes_received().

include/my_pthread.h

@@ -367,6 +367,26 @@ int my_pthread_mutex_trylock(pthread_mutex_t *mutex);
 } while(0)
 #endif /* !set_timespec_time_nsec */
 
+#ifdef MYSQL_CLIENT
+#define _current_thd() NULL
+#elif defined(_WIN32)
+#ifdef __cplusplus
+extern "C"
+#endif
+MYSQL_THD _current_thd_noinline();
+#define _current_thd() _current_thd_noinline()
+#else
+/*
+  THR_THD is a key which will be used to set/get THD* for a thread,
+  using my_pthread_setspecific_ptr()/my_thread_getspecific_ptr().
+*/
+extern pthread_key(MYSQL_THD, THR_THD);
+static inline MYSQL_THD _current_thd(void)
+{
+  return my_pthread_getspecific_ptr(MYSQL_THD,THR_THD);
+}
+#endif
+
 /* safe_mutex adds checking to mutex for easier debugging */
 struct st_hash;
 typedef struct st_safe_mutex_t

sql-common/client.c

@@ -3408,7 +3408,7 @@ CLI_MYSQL_REAL_CONNECT(MYSQL *mysql,const char *host, const char *user,
   if (mysql->options.extension && mysql->options.extension->async_context)
     net->vio->async_context= mysql->options.extension->async_context;
 
-  if (my_net_init(net, net->vio, 0, MYF(0)))
+  if (my_net_init(net, net->vio, _current_thd(), MYF(0)))
   {
     vio_delete(net->vio);
     net->vio = 0;

sql/mysqld.cc

@@ -6187,7 +6187,7 @@ static void bootstrap(MYSQL_FILE *file)
   thd->variables.wsrep_on= 0;
 #endif
   thd->bootstrap=1;
-  my_net_init(&thd->net,(st_vio*) 0, (void*) 0, MYF(0));
+  my_net_init(&thd->net,(st_vio*) 0, thd, MYF(0));
   thd->max_client_packet_length= thd->net.max_packet;
   thd->security_ctx->master_access= ~(ulong)0;
   thd->thread_id= thd->variables.pseudo_thread_id= thread_id++;

sql/mysqld.h

@@ -761,20 +761,6 @@ inline void dec_thread_running()
 
 void set_server_version(void);
 
-#if defined(MYSQL_DYNAMIC_PLUGIN) && defined(_WIN32)
-extern "C" THD *_current_thd_noinline();
-#define _current_thd() _current_thd_noinline()
-#else
-/*
-  THR_THD is a key which will be used to set/get THD* for a thread,
-  using my_pthread_setspecific_ptr()/my_thread_getspecific_ptr().
-*/
-extern pthread_key(THD*, THR_THD);
-inline THD *_current_thd(void)
-{
-  return my_pthread_getspecific_ptr(THD*,THR_THD);
-}
-#endif
 #define current_thd _current_thd()
 inline int set_current_thd(THD *thd)
 {

sql/sql_class.cc

@@ -369,16 +369,6 @@ void thd_close_connection(THD *thd)
     vio_close(thd->net.vio);
 }
 
-/**
-  Get current THD object from thread local data
-
-  @retval     The THD object for the thread, NULL if not connection thread
-*/
-THD *thd_get_current_thd()
-{
-  return current_thd;
-}
-
 /**
   Lock data that needs protection in THD object
 
@@ -4074,16 +4064,12 @@ my_bool thd_net_is_killed()
 
 void thd_increment_bytes_received(void *thd, ulong length)
 {
-  if (unlikely(!thd))                           // Called from federatedx
-    thd= current_thd;
   ((THD*) thd)->status_var.bytes_received+= length;
 }
 
 
 void thd_increment_net_big_packet_count(void *thd, ulong length)
 {
-  if (unlikely(!thd))                           // Called from federatedx
-    thd= current_thd;
   ((THD*) thd)->status_var.net_big_packet_count+= length;
 }