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authorJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
committerJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
commit0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch)
tree2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /nptl/pthread_mutex_setprioceiling.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
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2.5-18.1
Diffstat (limited to 'nptl/pthread_mutex_setprioceiling.c')
-rw-r--r--nptl/pthread_mutex_setprioceiling.c116
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
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+++ b/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 <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;
+}