glibc/nptl/pthread_rwlock_wrlock.c

88 lines
2.6 KiB
C
Raw Normal View History

/* Copyright (C) 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
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 <sysdep.h>
#include <lowlevellock.h>
#include <pthread.h>
#include <pthreadP.h>
/* Acquire write lock for RWLOCK. */
int
__pthread_rwlock_wrlock (rwlock)
pthread_rwlock_t *rwlock;
{
int result = 0;
/* Make sure we are along. */
lll_mutex_lock (rwlock->__data.__lock);
while (1)
{
/* Get the rwlock if there is no writer and no reader. */
if (rwlock->__data.__writer == 0 && rwlock->__data.__nr_readers == 0)
{
/* Mark self as writer. */
Update. 2003-06-05 Ulrich Drepper <drepper@redhat.com> * sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h (pthread_rwlock_t): Change type of __writer element to int. * sysdeps/unix/sysv/linux/ia64/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h: Likewise. * sysdeps/i386/tcb-offsets.sym: Replace SELF entry with TID entry. * sysdeps/x86_64/tcb-offsets.sym: Likewise. * pthread_rwlock_trywrlock.c: Store TID not self pointer in __writer. Compare with TID to determine deadlocks. * sysdeps/pthread/pthread_rwlock_rdlock.c: Likewise. * sysdeps/pthread/pthread_rwlock_timedrdlock.c: Likewise. * sysdeps/pthread/pthread_rwlock_timedwrlock.: Likewise. * sysdeps/pthread/pthread_rwlock_wrlock.c: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_rdlock.S: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_timedrdlock.S: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_timedwrlock.S: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_wrlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_rdlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_timedrdlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_timedwrlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_wrlock.S: Likewise. * Makefile (tests): Add tst-rwlock12. * tst-rwlock12.c: New file.
2003-06-05 21:31:57 +02:00
rwlock->__data.__writer = THREAD_GETMEM (THREAD_SELF, tid);
break;
}
/* Make sure we are not holding the rwlock as a writer. This is
a deadlock situation we recognize and report. */
Update. 2003-06-05 Ulrich Drepper <drepper@redhat.com> * sysdeps/unix/sysv/linux/i386/bits/pthreadtypes.h (pthread_rwlock_t): Change type of __writer element to int. * sysdeps/unix/sysv/linux/ia64/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h: Likewise. * sysdeps/unix/sysv/linux/x86_64/bits/pthreadtypes.h: Likewise. * sysdeps/i386/tcb-offsets.sym: Replace SELF entry with TID entry. * sysdeps/x86_64/tcb-offsets.sym: Likewise. * pthread_rwlock_trywrlock.c: Store TID not self pointer in __writer. Compare with TID to determine deadlocks. * sysdeps/pthread/pthread_rwlock_rdlock.c: Likewise. * sysdeps/pthread/pthread_rwlock_timedrdlock.c: Likewise. * sysdeps/pthread/pthread_rwlock_timedwrlock.: Likewise. * sysdeps/pthread/pthread_rwlock_wrlock.c: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_rdlock.S: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_timedrdlock.S: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_timedwrlock.S: Likewise. * sysdeps/unix/sysv/linux/i386/i486/pthread_rwlock_wrlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_rdlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_timedrdlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_timedwrlock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/pthread_rwlock_wrlock.S: Likewise. * Makefile (tests): Add tst-rwlock12. * tst-rwlock12.c: New file.
2003-06-05 21:31:57 +02:00
if (__builtin_expect (rwlock->__data.__writer
== THREAD_GETMEM (THREAD_SELF, tid), 0))
{
result = EDEADLK;
break;
}
/* Remember that we are a writer. */
if (++rwlock->__data.__nr_writers_queued == 0)
{
/* Overflow on number of queued writers. */
--rwlock->__data.__nr_writers_queued;
result = EAGAIN;
break;
}
int waitval = rwlock->__data.__writer_wakeup;
/* Free the lock. */
lll_mutex_unlock (rwlock->__data.__lock);
/* Wait for the writer or reader(s) to finish. */
lll_futex_wait (&rwlock->__data.__writer_wakeup, waitval);
/* Get the lock. */
lll_mutex_lock (rwlock->__data.__lock);
/* To start over again, remove the thread from the writer list. */
--rwlock->__data.__nr_writers_queued;
}
/* We are done, free the lock. */
lll_mutex_unlock (rwlock->__data.__lock);
return result;
}
weak_alias (__pthread_rwlock_wrlock, pthread_rwlock_wrlock)
strong_alias (__pthread_rwlock_wrlock, __pthread_rwlock_wrlock_internal)