Fixed and unified pthread_once.

[BZ #15215] This unifies various pthread_once architecture-specific
implementations which were using the same algorithm with slightly different
implementations.  It also adds missing memory barriers that are required for
correctness.

1 files changed, 0 insertions, 89 deletions

diff --git a/sysdeps/unix/sysv/linux/arm/nptl/pthread_once.c b/sysdeps/unix/sysv/linux/arm/nptl/pthread_once.c
deleted file mode 100644
index a063149925..0000000000
--- a/sysdeps/unix/sysv/linux/arm/nptl/pthread_once.c
+++ /dev/null
@@ -1,89 +0,0 @@
-/* Copyright (C) 2004-2014 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library.  If not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#include "pthreadP.h"
-#include <lowlevellock.h>
-
-unsigned long int __fork_generation attribute_hidden;
-
-static void
-clear_once_control (void *arg)
-{
-  pthread_once_t *once_control = (pthread_once_t *) arg;
-
-  *once_control = 0;
-  lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
-}
-
-int
-__pthread_once (pthread_once_t *once_control, void (*init_routine) (void))
-{
-  for (;;)
-    {
-      int oldval;
-      int newval;
-
-      /* Pseudo code:
-	 newval = __fork_generation | 1;
-	 oldval = *once_control;
-	 if ((oldval & 2) == 0)
-	   *once_control = newval;
-	 Do this atomically.
-      */
-      do
-	{
-	  newval = __fork_generation | 1;
-	  oldval = *once_control;
-	  if (oldval & 2)
-	    break;
-	} while (atomic_compare_and_exchange_val_acq (once_control, newval, oldval) != oldval);
-
-      /* Check if the initializer has already been done.  */
-      if ((oldval & 2) != 0)
-	return 0;
-
-      /* Check if another thread already runs the initializer.	*/
-      if ((oldval & 1) == 0)
-	break;
-
-      /* Check whether the initializer execution was interrupted by a fork.  */
-      if (oldval != newval)
-	break;
-
-      /* Same generation, some other thread was faster. Wait.  */
-      lll_futex_wait (once_control, oldval, LLL_PRIVATE);
-    }
-
-  /* This thread is the first here.  Do the initialization.
-     Register a cleanup handler so that in case the thread gets
-     interrupted the initialization can be restarted.  */
-  pthread_cleanup_push (clear_once_control, once_control);
-
-  init_routine ();
-
-  pthread_cleanup_pop (0);
-
-  /* Say that the initialisation is done.  */
-  *once_control = __fork_generation | 2;
-
-  /* Wake up all other threads.  */
-  lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
-
-  return 0;
-}
-weak_alias (__pthread_once, pthread_once)
-hidden_def (__pthread_once)