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.

15 files changed, 35 insertions, 71 deletions

diff --git a/sql/event_scheduler.cc b/sql/event_scheduler.cc
index 0e8e4826939..e842d95e3b0 100644
--- a/sql/event_scheduler.cc
+++ b/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;
 }
 
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 1c3af7349b9..faf7a244647 100644
--- a/sql/mysqld.cc
+++ b/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;
diff --git a/sql/mysqld.h b/sql/mysqld.h
index 8adfda0dfec..9cd0fe0a7fe 100644
--- a/sql/mysqld.h
+++ b/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
diff --git a/sql/slave.cc b/sql/slave.cc
index 381417c353b..fb26856f811 100644
--- a/sql/slave.cc
+++ b/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();
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 03383a744fc..591828b4306 100644
--- a/sql/sql_class.cc
+++ b/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;
 }
 
 /**
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 96ebfca3723..1069b49790a 100644
--- a/sql/sql_class.h
+++ b/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()
   {
diff --git a/sql/sql_connect.cc b/sql/sql_connect.cc
index aa9e561a717..dbe66650476 100644
--- a/sql/sql_connect.cc
+++ b/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 (;;)
   {
diff --git a/sql/sql_connect.h b/sql/sql_connect.h
index 4d62834a6f9..152bd71afd7 100644
--- a/sql/sql_connect.h
+++ b/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,
diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
index 2a2b74405f3..0914b4ac497 100644
--- a/sql/sql_insert.cc
+++ b/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()
 
     /*
diff --git a/sql/threadpool_common.cc b/sql/threadpool_common.cc
index 213b1baf5ab..50cc9aa43f2 100644
--- a/sql/threadpool_common.cc
+++ b/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;
diff --git a/sql/wsrep_mysqld.cc b/sql/wsrep_mysqld.cc
index 49880b2e827..7d54aab3ac0 100644
--- a/sql/wsrep_mysqld.cc
+++ b/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();
diff --git a/sql/wsrep_sst.cc b/sql/wsrep_sst.cc
index 8ffcb32e10a..93b7bc74489 100644
--- a/sql/wsrep_sst.cc
+++ b/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. */
diff --git a/sql/wsrep_thd.cc b/sql/wsrep_thd.cc
index 0f72c132d84..21a1c03d33e 100644
--- a/sql/wsrep_thd.cc
+++ b/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)
diff --git a/sql/wsrep_thd.h b/sql/wsrep_thd.h
index d24d8e6358f..c7350c79ee7 100644
--- a/sql/wsrep_thd.h
+++ b/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.
diff --git a/sql/wsrep_utils.cc b/sql/wsrep_utils.cc
index 59fa68db6c0..148def54aaf 100644
--- a/sql/wsrep_utils.cc
+++ b/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);
   }
 }