glibc/nptl/pthread_mutex_setprioceiling.c

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/* 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 <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_PRIVATE_NP) == 0)
return EINVAL;
if (prioceiling < 0 || __builtin_expect (prioceiling > 255, 0))
return EINVAL;
/* XXX This needs to lock with TID, but shouldn't obey priority protect
protocol. */
/* lll_xxx_mutex_lock (mutex->__data.__lock); */
if (old_ceiling != NULL)
*old_ceiling = (mutex->__data.__kind & PTHREAD_MUTEX_PRIO_CEILING_MASK)
>> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
int newkind = (mutex->__data.__kind & ~PTHREAD_MUTEX_PRIO_CEILING_MASK);
mutex->__data.__kind = newkind
| (prioceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT);
/* XXX This needs to unlock the above special kind of lock. */
/* lll_xxx_mutex_unlock (mutex->__data.__lock); */
return 0;
}