posix: Implement self-contained POSIX barriers

POSIX barriers are now available in all configurations and no longer
depend on --enable-posix.

Update #2514.
Update #3114.

1 files changed, 36 insertions, 22 deletions

diff --git a/cpukit/posix/src/pbarrierwait.c b/cpukit/posix/src/pbarrierwait.c
index 117beac553..9719112256 100644
--- a/cpukit/posix/src/pbarrierwait.c
+++ b/cpukit/posix/src/pbarrierwait.c
@@ -9,6 +9,8 @@
  *  COPYRIGHT (c) 1989-2007.
  *  On-Line Applications Research Corporation (OAR).
  *
+ *  Copyright (c) 2017 embedded brains GmbH
+ *
  *  The license and distribution terms for this file may be
  *  found in the file LICENSE in this distribution or at
  *  http://www.rtems.org/license/LICENSE.
@@ -21,32 +23,44 @@
 #include <rtems/posix/barrierimpl.h>
 #include <rtems/posix/posixapi.h>
 
-THREAD_QUEUE_OBJECT_ASSERT( POSIX_Barrier_Control, Barrier.Wait_queue );
-
-int pthread_barrier_wait(
-  pthread_barrier_t *barrier
-)
+int pthread_barrier_wait( pthread_barrier_t *_barrier )
 {
-  POSIX_Barrier_Control *the_barrier;
+  POSIX_Barrier_Control *barrier;
   Thread_queue_Context   queue_context;
-  Status_Control         status;
+  Thread_Control        *executing;
+  unsigned int           waiting_threads;
 
-  if ( barrier == NULL ) {
-    return EINVAL;
-  }
+  POSIX_BARRIER_VALIDATE_OBJECT( _barrier );
 
-  the_barrier = _POSIX_Barrier_Get( barrier, &queue_context );
+  barrier = _POSIX_Barrier_Get( _barrier );
 
-  if ( the_barrier == NULL ) {
-    return EINVAL;
-  }
+  executing = _POSIX_Barrier_Queue_acquire( barrier, &queue_context );
+  waiting_threads = barrier->waiting_threads;
+  ++waiting_threads;
 
-  _Thread_queue_Context_set_no_timeout( &queue_context );
-  status = _CORE_barrier_Seize(
-    &the_barrier->Barrier,
-    _Thread_Executing,
-    true,
-    &queue_context
-  );
-  return _POSIX_Get_error( status );
+  if ( waiting_threads == barrier->count ) {
+    barrier->waiting_threads = 0;
+    _Thread_queue_Flush_critical(
+      &barrier->Queue.Queue,
+      POSIX_BARRIER_TQ_OPERATIONS,
+      _Thread_queue_Flush_default_filter,
+      &queue_context
+    );
+    return PTHREAD_BARRIER_SERIAL_THREAD;
+  } else {
+    barrier->waiting_threads = waiting_threads;
+    _Thread_queue_Context_set_thread_state(
+      &queue_context,
+      STATES_WAITING_FOR_BARRIER
+    );
+    _Thread_queue_Context_set_do_nothing_enqueue_callout( &queue_context );
+    _Thread_queue_Context_set_no_timeout( &queue_context );
+    _Thread_queue_Enqueue(
+      &barrier->Queue.Queue,
+      POSIX_BARRIER_TQ_OPERATIONS,
+      executing,
+      &queue_context
+    );
+    return 0;
+  }
 }