cvs update pthreads

1 files changed, 104 insertions, 99 deletions

diff --git a/pthreads/pthread_barrier_wait.c b/pthreads/pthread_barrier_wait.c
index 01ae29766..a19582583 100644
--- a/pthreads/pthread_barrier_wait.c
+++ b/pthreads/pthread_barrier_wait.c
@@ -1,99 +1,104 @@
-/*
- * pthread_barrier_wait.c
- *
- * Description:
- * This translation unit implements barrier primitives.
- *
- * --------------------------------------------------------------------------
- *
- *      Pthreads-win32 - POSIX Threads Library for Win32
- *      Copyright(C) 1998 John E. Bossom
- *      Copyright(C) 1999,2005 Pthreads-win32 contributors
- * 
- *      Contact Email: rpj@callisto.canberra.edu.au
- * 
- *      The current list of contributors is contained
- *      in the file CONTRIBUTORS included with the source
- *      code distribution. The list can also be seen at the
- *      following World Wide Web location:
- *      http://sources.redhat.com/pthreads-win32/contributors.html
- * 
- *      This 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 of the License, or (at your option) any later version.
- * 
- *      This 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 this library in the file COPYING.LIB;
- *      if not, write to the Free Software Foundation, Inc.,
- *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
- */
-
-#include "pthread.h"
-#include "implement.h"
-
-
-int
-pthread_barrier_wait (pthread_barrier_t * barrier)
-{
-  int result;
-  int step;
-  pthread_barrier_t b;
-
-  if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)
-    {
-      return EINVAL;
-    }
-
-  b = *barrier;
-  step = b->iStep;
-
-  if (0 == InterlockedDecrement ((long *) &(b->nCurrentBarrierHeight)))
-    {
-      /* Must be done before posting the semaphore. */
-      b->nCurrentBarrierHeight = b->nInitialBarrierHeight;
-
-      /*
-       * There is no race condition between the semaphore wait and post
-       * because we are using two alternating semas and all threads have
-       * entered barrier_wait and checked nCurrentBarrierHeight before this
-       * barrier's sema can be posted. Any threads that have not quite
-       * entered sem_wait below when the multiple_post has completed
-       * will nevertheless continue through the semaphore (barrier)
-       * and will not be left stranded.
-       */
-      result = (b->nInitialBarrierHeight > 1
-		? sem_post_multiple (&(b->semBarrierBreeched[step]),
-				     b->nInitialBarrierHeight - 1) : 0);
-    }
-  else
-    {
-      /*
-       * Use the non-cancelable version of sem_wait().
-       */
-      result = ptw32_semwait (&(b->semBarrierBreeched[step]));
-    }
-
-  /*
-   * The first thread across will be the PTHREAD_BARRIER_SERIAL_THREAD.
-   * This also sets up the alternate semaphore as the next barrier.
-   */
-  if (0 == result)
-    {
-      result = ((PTW32_INTERLOCKED_LONG) step ==
-		PTW32_INTERLOCKED_COMPARE_EXCHANGE ((PTW32_INTERLOCKED_LPLONG)
-						    & (b->iStep),
-						    (PTW32_INTERLOCKED_LONG)
-						    (1L - step),
-						    (PTW32_INTERLOCKED_LONG)
-						    step) ?
-		PTHREAD_BARRIER_SERIAL_THREAD : 0);
-    }
-
-  return (result);
-}
+/*

+ * pthread_barrier_wait.c

+ *

+ * Description:

+ * This translation unit implements barrier primitives.

+ *

+ * --------------------------------------------------------------------------

+ *

+ *      Pthreads-win32 - POSIX Threads Library for Win32

+ *      Copyright(C) 1998 John E. Bossom

+ *      Copyright(C) 1999,2005 Pthreads-win32 contributors

+ * 

+ *      Contact Email: rpj@callisto.canberra.edu.au

+ * 

+ *      The current list of contributors is contained

+ *      in the file CONTRIBUTORS included with the source

+ *      code distribution. The list can also be seen at the

+ *      following World Wide Web location:

+ *      http://sources.redhat.com/pthreads-win32/contributors.html

+ * 

+ *      This 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 of the License, or (at your option) any later version.

+ * 

+ *      This 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 this library in the file COPYING.LIB;

+ *      if not, write to the Free Software Foundation, Inc.,

+ *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

+ */

+

+#include "pthread.h"

+#include "implement.h"

+

+

+int

+pthread_barrier_wait (pthread_barrier_t * barrier)

+{

+  int result;

+  pthread_barrier_t b;

+

+  ptw32_mcs_local_node_t node;

+

+  if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)

+    {

+      return EINVAL;

+    }

+

+  ptw32_mcs_lock_acquire((ptw32_mcs_lock_t *)&(*barrier)->lock, &node);

+

+  b = *barrier;

+  if (--b->nCurrentBarrierHeight == 0)

+    {

+      /*

+       * We are the last thread to arrive at the barrier before it releases us.

+       * Move our MCS local node to the global scope barrier handle so that the

+       * last thread out (not necessarily us) can release the lock.

+       */

+      ptw32_mcs_node_substitute(&b->proxynode, &node);

+

+      /*

+       * Any threads that have not quite entered sem_wait below when the

+       * multiple_post has completed will nevertheless continue through

+       * the semaphore (barrier).

+       */

+      result = (b->nInitialBarrierHeight > 1

+                ? sem_post_multiple (&(b->semBarrierBreeched),

+				     b->nInitialBarrierHeight - 1) : 0);

+    }

+  else

+    {

+      ptw32_mcs_lock_release(&node);

+      /*

+       * Use the non-cancelable version of sem_wait().

+       *

+       * It is possible that all nInitialBarrierHeight-1 threads are

+       * at this point when the last thread enters the barrier, resets

+       * nCurrentBarrierHeight = nInitialBarrierHeight and leaves.

+       * If pthread_barrier_destroy is called at that moment then the

+       * barrier will be destroyed along with the semas.

+       */

+      result = ptw32_semwait (&(b->semBarrierBreeched));

+    }

+

+  if ((PTW32_INTERLOCKED_LONG)InterlockedIncrement((LPLONG)&b->nCurrentBarrierHeight)

+		  == (PTW32_INTERLOCKED_LONG)b->nInitialBarrierHeight)

+    {

+  /*

+       * We are the last thread to cross this barrier

+   */

+      ptw32_mcs_lock_release(&b->proxynode);

+  if (0 == result)

+    {

+          result = PTHREAD_BARRIER_SERIAL_THREAD;

+        }

+    }

+

+  return (result);

+}