MDEV-22437 make THR_THD* variable thread_local

Now all access goes through _current_thd() and set_current_thd()
functions.

Some functions like THD::store_globals() can not fail now.

extra/mariabackup/xtrabackup.cc

@@ -6021,9 +6021,6 @@ int main(int argc, char **argv)
 	init_signals();
 	MY_INIT(argv[0]);
 
-	pthread_key_create(&THR_THD, NULL);
-	my_pthread_setspecific_ptr(THR_THD, NULL);
-
 	xb_regex_init();
 
 	capture_tool_command(argc, argv);
@@ -6070,9 +6067,6 @@ int main(int argc, char **argv)
 	}
 #endif
 
-	if (THR_THD)
-		(void) pthread_key_delete(THR_THD);
-
 	logger.cleanup_base();
 	cleanup_errmsgs();
 	free_error_messages();

include/my_pthread.h

@@ -360,22 +360,8 @@ size_t my_setstacksize(pthread_attr_t *attr, size_t stacksize);
 
 #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);
-}
+MYSQL_THD _current_thd();
 #endif
 
 /* safe_mutex adds checking to mutex for easier debugging */

libmysqld/lib_sql.cc

@@ -437,7 +437,7 @@ static void emb_free_embedded_thd(MYSQL *mysql)
   thd->clear_data_list();
   thd->store_globals();
   delete thd;
-  my_pthread_setspecific_ptr(THR_THD,  0);
+  set_current_thd(nullptr);
   mysql->thd=0;
 }
 
@@ -683,11 +683,7 @@ void *create_embedded_thd(int client_flag)
   THD * thd= new THD(next_thread_id());
 
   thd->thread_stack= (char*) &thd;
-  if (thd->store_globals())
-  {
-    fprintf(stderr,"store_globals failed.\n");
-    goto err;
-  }
+  thd->store_globals();
   lex_start(thd);
 
   /* TODO - add init_connect command execution */
@@ -714,9 +710,6 @@ void *create_embedded_thd(int client_flag)
   thd->mysys_var= 0;
   thd->reset_globals();
   return thd;
-err:
-  delete(thd);
-  return NULL;
 }
 
 

plugin/feedback/sender_thread.cc

@@ -92,8 +92,7 @@ static int prepare_for_fill(TABLE_LIST *tables)
   thd->variables.pseudo_thread_id= thd->thread_id;
   server_threads.insert(thd);
   thd->thread_stack= (char*) &tables;
-  if (thd->store_globals())
-    return 1;
+  thd->store_globals();
 
   thd->mysys_var->current_cond= &sleep_condition;
   thd->mysys_var->current_mutex= &sleep_mutex;

plugin/handler_socket/handlersocket/database.cpp

@@ -302,7 +302,7 @@ dbcontext::init_thread(const void *stack_bottom, volatile int& shutdown_flag)
       thd->db.length= sizeof("handlersocket")-1;
     }
     thd->variables.option_bits |= OPTION_TABLE_LOCK;
-    my_pthread_setspecific_ptr(THR_THD, thd);
+    set_current_thd(thd);
     DBG_THR(fprintf(stderr, "HNDSOCK x0 %p\n", thd));
   }
   {
@@ -339,7 +339,7 @@ dbcontext::term_thread()
 {
   DBG_THR(fprintf(stderr, "HNDSOCK thread end %p\n", thd));
   close_tables_if();
-  my_pthread_setspecific_ptr(THR_THD, 0);
+  set_current_thd(nullptr);
   {
     delete thd;
     thd = 0;

sql/event_scheduler.cc

@@ -128,11 +128,12 @@ bool
 post_init_event_thread(THD *thd)
 {
   (void) init_new_connection_handler_thread();
-  if (init_thr_lock() || thd->store_globals())
+  if (init_thr_lock())
   {
     thd->cleanup();
     return TRUE;
   }
+  thd->store_globals();
   return FALSE;
 }
 

sql/mysqld.cc

@@ -666,7 +666,10 @@ static std::atomic<char*> shutdown_user;
 
 /* Thread specific variables */
 
-pthread_key(THD*, THR_THD);
+static thread_local THD *THR_THD;
+
+MYSQL_THD _current_thd() { return THR_THD; }
+void set_current_thd(THD *thd) { THR_THD= thd; }
 
 /*
   LOCK_start_thread is used to syncronize thread start and stop with
@@ -1917,13 +1920,6 @@ extern "C" void unireg_abort(int exit_code)
 }
 
 
-static void cleanup_tls()
-{
-  if (THR_THD)
-    (void)pthread_key_delete(THR_THD);
-}
-
-
 static void mysqld_exit(int exit_code)
 {
   DBUG_ENTER("mysqld_exit");
@@ -1952,7 +1948,6 @@ static void mysqld_exit(int exit_code)
     if (exit_code == 0)
       SAFEMALLOC_REPORT_MEMORY(0);
   }
-  cleanup_tls();
   DBUG_LEAVE;
   sd_notify(0, "STATUS=MariaDB server is down");
   exit(exit_code); /* purecov: inspected */
@@ -3691,11 +3686,6 @@ static const char *rpl_make_log_name(PSI_memory_key key, const char *opt,
 
 static int init_early_variables()
 {
-  if (pthread_key_create(&THR_THD, NULL))
-  {
-    fprintf(stderr, "Fatal error: Can't create thread-keys\n");
-    return 1;
-  }
   set_current_thd(0);
   set_malloc_size_cb(my_malloc_size_cb_func);
   global_status_var.global_memory_used= 0;

sql/mysqld.h

@@ -769,8 +769,6 @@ extern char *opt_ssl_ca, *opt_ssl_capath, *opt_ssl_cert, *opt_ssl_cipher,
   *opt_ssl_key, *opt_ssl_crl, *opt_ssl_crlpath;
 extern ulonglong tls_version;
 
-extern MYSQL_PLUGIN_IMPORT pthread_key(THD*, THR_THD);
-
 #ifdef MYSQL_SERVER
 
 /**
@@ -928,11 +926,7 @@ inline void table_case_convert(char * name, uint length)
 extern void set_server_version(char *buf, size_t size);
 
 #define current_thd _current_thd()
-inline int set_current_thd(THD *thd)
-{
-  return my_pthread_setspecific_ptr(THR_THD, thd);
-}
-
+void set_current_thd(THD *thd);
 
 /*
   @todo remove, make it static in ha_maria.cc

sql/slave.cc

@@ -3628,9 +3628,16 @@ static int init_slave_thread(THD* thd, Master_info *mi,
   thd->system_thread = (thd_type == SLAVE_THD_SQL) ?
     SYSTEM_THREAD_SLAVE_SQL : SYSTEM_THREAD_SLAVE_IO;
 
+  if (init_thr_lock())
+  {
+    thd->cleanup();
+    DBUG_RETURN(-1);
+  }
+
   /* We must call store_globals() before doing my_net_init() */
-  if (init_thr_lock() || thd->store_globals() ||
-      my_net_init(&thd->net, 0, thd, MYF(MY_THREAD_SPECIFIC)) ||
+  thd->store_globals();
+
+  if (my_net_init(&thd->net, 0, thd, MYF(MY_THREAD_SPECIFIC)) ||
       IF_DBUG(simulate_error & (1<< thd_type), 0))
   {
     thd->cleanup();

sql/sql_class.cc

@@ -1214,11 +1214,6 @@ void thd_gmt_sec_to_TIME(MYSQL_THD thd, MYSQL_TIME *ltime, my_time_t t)
 
 
 #ifdef _WIN32
-extern "C"   THD *_current_thd_noinline(void)
-{
-  return my_pthread_getspecific_ptr(THD*,THR_THD);
-}
-
 extern "C" my_thread_id next_thread_id_noinline()
 {
 #undef next_thread_id
@@ -2152,7 +2147,7 @@ void THD::reset_killed()
   the structure for the net buffer
 */
 
-bool THD::store_globals()
+void THD::store_globals()
 {
   /*
     Assert that thread_stack is initialized: it's necessary to be able
@@ -2160,8 +2155,7 @@ bool THD::store_globals()
   */
   DBUG_ASSERT(thread_stack);
 
-  if (set_current_thd(this))
-    return 1;
+  set_current_thd(this);
   /*
     mysys_var is concurrently readable by a killer thread.
     It is protected by LOCK_thd_kill, it is not needed to lock while the
@@ -2203,8 +2197,6 @@ bool THD::store_globals()
     created in another thread
   */
   thr_lock_info_init(&lock_info, mysys_var);
-
-  return 0;
 }
 
 /**

sql/sql_class.h

@@ -3390,7 +3390,7 @@ public:
   void cleanup_after_query();
   void free_connection();
   void reset_for_reuse();
-  bool store_globals();
+  void store_globals();
   void reset_globals();
   bool trace_started()
   {

sql/sql_connect.cc

@@ -1105,16 +1105,9 @@ static int check_connection(THD *thd)
         In this case we will close the connection and increment status
 */
 
-bool setup_connection_thread_globals(THD *thd)
+void setup_connection_thread_globals(THD *thd)
 {
-  if (thd->store_globals())
-  {
-    close_connection(thd, ER_OUT_OF_RESOURCES);
-    statistic_increment(aborted_connects,&LOCK_status);
-    statistic_increment(connection_errors_internal, &LOCK_status);
-    return 1;                                   // Error
-  }
-  return 0;
+  thd->store_globals();
 }
 
 
@@ -1397,12 +1390,7 @@ void do_handle_one_connection(CONNECT *connect, bool put_in_cache)
     stack overruns.
   */
   thd->thread_stack= (char*) &thd;
-  if (setup_connection_thread_globals(thd))
-  {
-    unlink_thd(thd);
-    delete thd;
-    return;
-  }
+  setup_connection_thread_globals(thd);
 
   for (;;)
   {

sql/sql_connect.h

@@ -82,7 +82,7 @@ void decrease_user_connections(USER_CONN *uc);
 #define decrease_user_connections(X) do { } while(0)       /* nothing */
 #endif
 bool thd_init_client_charset(THD *thd, uint cs_number);
-bool setup_connection_thread_globals(THD *thd);
+void setup_connection_thread_globals(THD *thd);
 bool thd_prepare_connection(THD *thd);
 bool thd_is_connection_alive(THD *thd);
 int thd_set_peer_addr(THD *thd, sockaddr_storage *addr,

sql/sql_insert.cc

@@ -3087,15 +3087,16 @@ pthread_handler_t handle_delayed_insert(void *arg)
   {
     DBUG_ENTER("handle_delayed_insert");
     thd->thread_stack= (char*) &thd;
-    if (init_thr_lock() || thd->store_globals())
+    if (init_thr_lock())
     {
-      /* Can't use my_error since store_globals has perhaps failed */
       thd->get_stmt_da()->set_error_status(ER_OUT_OF_RESOURCES);
       di->handler_thread_initialized= TRUE;
       thd->fatal_error();
       goto err;
     }
 
+    thd->store_globals();
+
     thd->lex->sql_command= SQLCOM_INSERT;        // For innodb::store_lock()
 
     /*

sql/threadpool_common.cc

@@ -96,7 +96,7 @@ struct Worker_thread_context
   {
     PSI_CALL_set_thread(psi_thread);
     set_mysys_var(mysys_var);
-    pthread_setspecific(THR_THD, 0);
+    set_current_thd(nullptr);
   }
 };
 
@@ -255,8 +255,7 @@ static THD* threadpool_add_connection(CONNECT *connect, void *scheduler_data)
   thd->start_utime= now;
   thd->thr_create_utime= now;
 
-  if (setup_connection_thread_globals(thd))
-    goto end;
+  setup_connection_thread_globals(thd);
 
   if (thd_prepare_connection(thd))
     goto end;

sql/wsrep_mysqld.cc

@@ -1103,7 +1103,7 @@ void wsrep_shutdown_replication()
   node_uuid= WSREP_UUID_UNDEFINED;
 
   /* Undocking the thread specific data. */
-  my_pthread_setspecific_ptr(THR_THD, NULL);
+  set_current_thd(nullptr);
 }
 
 bool wsrep_start_replication()
@@ -2926,15 +2926,7 @@ void* start_wsrep_THD(void *arg)
 
   thd->thread_stack= (char*) &thd;
   wsrep_assign_from_threadvars(thd);
-  if (wsrep_store_threadvars(thd))
-  {
-    close_connection(thd, ER_OUT_OF_RESOURCES);
-    statistic_increment(aborted_connects,&LOCK_status);
-    unlink_thd(thd);
-    delete thd;
-    delete thd_args;
-    goto error;
-  }
+  wsrep_store_threadvars(thd);
 
   thd->system_thread= SYSTEM_THREAD_SLAVE_SQL;
   thd->security_ctx->skip_grants();

sql/wsrep_sst.cc

@@ -364,7 +364,7 @@ void wsrep_sst_received (THD*                thd,
       wsrep_store_threadvars(thd);
     }
     else {
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
     }
 
     /* During sst WSREP(thd) is not yet set for joiner. */

sql/wsrep_thd.cc

@@ -454,13 +454,13 @@ void wsrep_restore_threadvars(const Wsrep_threadvars& globals)
   pthread_setspecific(THR_KEY_mysys, globals.mysys_var);
 }
 
-int wsrep_store_threadvars(THD *thd)
+void wsrep_store_threadvars(THD *thd)
 {
   if (thread_handling ==  SCHEDULER_TYPES_COUNT)
   {
     pthread_setspecific(THR_KEY_mysys, thd->mysys_var);
   }
-  return thd->store_globals();
+  thd->store_globals();
 }
 
 void wsrep_reset_threadvars(THD *thd)

sql/wsrep_thd.h

@@ -162,7 +162,7 @@ void wsrep_restore_threadvars(const Wsrep_threadvars&);
 /**
    Store variables into thread local storage.
 */
-int wsrep_store_threadvars(THD *);
+void wsrep_store_threadvars(THD *);
 
 /**
    Reset thread local storage.

sql/wsrep_utils.cc

@@ -436,7 +436,7 @@ thd::~thd ()
   if (ptr)
   {
     delete ptr;
-    my_pthread_setspecific_ptr (THR_THD, 0);
+    set_current_thd(nullptr);
   }
 }
 

storage/spider/spd_conn.cc

@@ -2519,7 +2519,7 @@ void *spider_bg_conn_action(
     pthread_cond_signal(&conn->bg_conn_sync_cond);
     pthread_mutex_unlock(&conn->bg_conn_sync_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     DBUG_RETURN(NULL);
@@ -2583,7 +2583,7 @@ void *spider_bg_conn_action(
       pthread_mutex_unlock(&conn->bg_conn_mutex);
       pthread_mutex_unlock(&conn->bg_conn_sync_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
 #endif
       my_thread_end();
       DBUG_RETURN(NULL);
@@ -3035,7 +3035,7 @@ void *spider_bg_sts_action(
     share->bg_sts_init = FALSE;
     pthread_mutex_unlock(&share->sts_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     my_afree(need_mons);
@@ -3095,7 +3095,7 @@ void *spider_bg_sts_action(
     share->bg_sts_init = FALSE;
     pthread_mutex_unlock(&share->sts_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     my_afree(need_mons);
@@ -3124,7 +3124,7 @@ void *spider_bg_sts_action(
       pthread_cond_signal(&share->bg_sts_sync_cond);
       pthread_mutex_unlock(&share->sts_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
 #endif
       my_thread_end();
       my_afree(need_mons);
@@ -3401,7 +3401,7 @@ void *spider_bg_crd_action(
     share->bg_crd_init = FALSE;
     pthread_mutex_unlock(&share->crd_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     my_afree(need_mons);
@@ -3465,7 +3465,7 @@ void *spider_bg_crd_action(
     share->bg_crd_init = FALSE;
     pthread_mutex_unlock(&share->crd_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     my_afree(need_mons);
@@ -3494,7 +3494,7 @@ void *spider_bg_crd_action(
       pthread_cond_signal(&share->bg_crd_sync_cond);
       pthread_mutex_unlock(&share->crd_mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
 #endif
       my_thread_end();
       my_afree(need_mons);
@@ -3893,7 +3893,7 @@ void *spider_bg_mon_action(
     pthread_cond_signal(&share->bg_mon_conds[link_idx]);
     pthread_mutex_unlock(&share->bg_mon_mutexes[link_idx]);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     DBUG_RETURN(NULL);
@@ -3932,7 +3932,7 @@ void *spider_bg_mon_action(
       spider_free_trx(trx, TRUE);
       delete thd;
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
 #endif
       my_thread_end();
       DBUG_RETURN(NULL);

storage/spider/spd_table.cc

@@ -9967,7 +9967,7 @@ void *spider_table_bg_sts_action(
     thread->killed = FALSE;
     pthread_mutex_unlock(&thread->mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     DBUG_RETURN(NULL);
@@ -10034,7 +10034,7 @@ void *spider_table_bg_sts_action(
       pthread_cond_signal(&thread->sync_cond);
       pthread_mutex_unlock(&thread->mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
 #endif
       my_thread_end();
       DBUG_RETURN(NULL);
@@ -10166,7 +10166,7 @@ void *spider_table_bg_crd_action(
     thread->killed = FALSE;
     pthread_mutex_unlock(&thread->mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-    my_pthread_setspecific_ptr(THR_THD, NULL);
+    set_current_thd(nullptr);
 #endif
     my_thread_end();
     DBUG_RETURN(NULL);
@@ -10186,7 +10186,7 @@ void *spider_table_bg_crd_action(
       pthread_cond_signal(&thread->sync_cond);
       pthread_mutex_unlock(&thread->mutex);
 #if !defined(MYSQL_DYNAMIC_PLUGIN) || !defined(_WIN32)
-      my_pthread_setspecific_ptr(THR_THD, NULL);
+      set_current_thd(nullptr);
 #endif
       my_thread_end();
       DBUG_RETURN(NULL);

storage/spider/spd_trx.cc

@@ -4173,8 +4173,7 @@ THD *spider_create_tmp_thd()
   thd->thread_id = thd->variables.pseudo_thread_id = 0;
 #endif
   thd->thread_stack = (char*) &thd;
-  if (thd->store_globals())
-    DBUG_RETURN(NULL);
+  thd->store_globals();
   lex_start(thd);
   DBUG_RETURN(thd);
 }