mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 04:50:07 +00:00
b45b1c5ba1
The idea is to make NPTL implementation to use on the functions provided by futex-internal.h. Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Lukasz Majewski <lukma@denx.de>
124 lines
3.7 KiB
C
124 lines
3.7 KiB
C
/* Set current priority ceiling of pthread_mutex_t.
|
|
Copyright (C) 2006-2020 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, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <stdbool.h>
|
|
#include <errno.h>
|
|
#include <pthreadP.h>
|
|
#include <atomic.h>
|
|
#include <futex-internal.h>
|
|
|
|
|
|
int
|
|
pthread_mutex_setprioceiling (pthread_mutex_t *mutex, int prioceiling,
|
|
int *old_ceiling)
|
|
{
|
|
/* See concurrency notes regarding __kind in struct __pthread_mutex_s
|
|
in sysdeps/nptl/bits/thread-shared-types.h. */
|
|
if ((atomic_load_relaxed (&(mutex->__data.__kind))
|
|
& PTHREAD_MUTEX_PRIO_PROTECT_NP) == 0)
|
|
return EINVAL;
|
|
|
|
/* See __init_sched_fifo_prio. */
|
|
if (atomic_load_relaxed (&__sched_fifo_min_prio) == -1
|
|
|| atomic_load_relaxed (&__sched_fifo_max_prio) == -1)
|
|
__init_sched_fifo_prio ();
|
|
|
|
if (__glibc_unlikely (prioceiling
|
|
< atomic_load_relaxed (&__sched_fifo_min_prio))
|
|
|| __glibc_unlikely (prioceiling
|
|
> atomic_load_relaxed (&__sched_fifo_max_prio))
|
|
|| __glibc_unlikely ((prioceiling
|
|
& (PTHREAD_MUTEXATTR_PRIO_CEILING_MASK
|
|
>> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT))
|
|
!= prioceiling))
|
|
return EINVAL;
|
|
|
|
/* Check whether we already hold the mutex. */
|
|
bool locked = false;
|
|
int kind = PTHREAD_MUTEX_TYPE (mutex);
|
|
if (mutex->__data.__owner == THREAD_GETMEM (THREAD_SELF, tid))
|
|
{
|
|
if (kind == PTHREAD_MUTEX_PP_ERRORCHECK_NP)
|
|
return EDEADLK;
|
|
|
|
if (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)
|
|
futex_wait ((unsigned int *) &mutex->__data.__lock, ceilval | 2,
|
|
PTHREAD_MUTEX_PSHARED (mutex));
|
|
}
|
|
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 ();
|
|
|
|
futex_wake ((unsigned int *)&mutex->__data.__lock, INT_MAX,
|
|
PTHREAD_MUTEX_PSHARED (mutex));
|
|
|
|
return 0;
|
|
}
|