2.5-18.1

1 files changed, 116 insertions, 0 deletions

diff --git a/nptl/pthread_mutex_setprioceiling.c b/nptl/pthread_mutex_setprioceiling.c
new file mode 100644
index 0000000000..cd13d1c14c
--- /dev/null
+++ b/nptl/pthread_mutex_setprioceiling.c
@@ -0,0 +1,116 @@
+/* Set current priority ceiling of pthread_mutex_t.
+   Copyright (C) 2006 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <stdbool.h>
+#include <errno.h>
+#include <pthreadP.h>
+
+
+int
+pthread_mutex_setprioceiling (mutex, prioceiling, old_ceiling)
+     pthread_mutex_t *mutex;
+     int prioceiling;
+     int *old_ceiling;
+{
+  /* The low bits of __kind aren't ever changed after pthread_mutex_init,
+     so we don't need a lock yet.  */
+  if ((mutex->__data.__kind & PTHREAD_MUTEX_PRIO_PROTECT_NP) == 0)
+    return EINVAL;
+
+  if (__sched_fifo_min_prio == -1)
+    __init_sched_fifo_prio ();
+
+  if (__builtin_expect (prioceiling < __sched_fifo_min_prio, 0)
+      || __builtin_expect (prioceiling > __sched_fifo_max_prio, 0)
+      || __builtin_expect ((prioceiling
+			    & (PTHREAD_MUTEXATTR_PRIO_CEILING_MASK
+			       >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT))
+			   != prioceiling, 0))
+    return EINVAL;
+
+  /* Check whether we already hold the mutex.  */
+  bool locked = false;
+  if (mutex->__data.__owner == THREAD_GETMEM (THREAD_SELF, tid))
+    {
+      if (mutex->__data.__kind == PTHREAD_MUTEX_PP_ERRORCHECK_NP)
+	return EDEADLK;
+
+      if (mutex->__data.__kind == PTHREAD_MUTEX_PP_RECURSIVE_NP)
+	locked = true;
+    }
+
+  int oldval = mutex->__data.__lock;
+  if (! locked)
+    do
+      {
+	/* Need to lock the mutex, but without obeying the priority
+	   protect protocol.  */
+	int ceilval = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK);
+
+	oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+						      ceilval | 1, ceilval);
+	if (oldval == ceilval)
+	  break;
+
+	do
+	  {
+	    oldval
+	      = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+						     ceilval | 2,
+						     ceilval | 1);
+
+	    if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval)
+	      break;
+
+	    if (oldval != ceilval)
+	      lll_futex_wait (&mutex->__data.__lock, ceilval | 2);
+	  }
+	while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
+						    ceilval | 2, ceilval)
+	       != ceilval);
+
+	if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval)
+	  continue;
+      }
+    while (0);
+
+  int oldprio = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK)
+		>> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
+  if (locked)
+    {
+      int ret = __pthread_tpp_change_priority (oldprio, prioceiling);
+      if (ret)
+	return ret;
+    }
+
+  if (old_ceiling != NULL)
+    *old_ceiling = oldprio;
+
+  int newlock = 0;
+  if (locked)
+    newlock = (mutex->__data.__lock & ~PTHREAD_MUTEX_PRIO_CEILING_MASK);
+  mutex->__data.__lock = newlock
+			 | (prioceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT);
+  atomic_full_barrier ();
+
+  lll_futex_wake (&mutex->__data.__lock, INT_MAX);
+
+  return 0;
+}