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authorUlrich Drepper <drepper@redhat.com>2006-10-28 05:15:26 +0000
committerUlrich Drepper <drepper@redhat.com>2006-10-28 05:15:26 +0000
commiteb0a3d0cab507fecefe390a340f74ab8e5cf7831 (patch)
treec97ac1c33a78c454c0aeb520624af29c724355d2 /nptl/pthread_cond_wait.c
parent006a8f6f626e6e4d30b73c2ee20377b6a8cce1b7 (diff)
downloadglibc-eb0a3d0cab507fecefe390a340f74ab8e5cf7831.tar.gz
* sysdeps/pthread/pthread_barrier_wait.c: Move to...
* pthread_barrier_wait.c: ...here. * sysdeps/pthread/pthread_cond_broadcast.c: Move to... * pthread_cond_broadcast.c: ...here. * sysdeps/pthread/pthread_cond_signal.c: Move to... * pthread_cond_signal.c: ...here. * sysdeps/pthread/pthread_cond_timedwait.c: Move to... * pthread_cond_timedwait.c: ...here. * sysdeps/pthread/pthread_cond_wait.c: Move to... * pthread_cond_wait.c: ...here. * sysdeps/pthread/pthread_once.c: Move to... * pthread_once.c: ...here. * sysdeps/pthread/pthread_rwlock_rdlock.c: Move to... * pthread_rwlock_rdlock.c: ...here. * sysdeps/pthread/pthread_rwlock_timedrdlock.c: Move to... * pthread_rwlock_timedrdlock.c: ...here. * sysdeps/pthread/pthread_rwlock_timedwrlock.c: Move to... * pthread_rwlock_timedwrlock.c: ...here. * sysdeps/pthread/pthread_rwlock_unlock.c: Move to... * pthread_rwlock_unlock.c: ...here. * sysdeps/pthread/pthread_rwlock_wrlock.c: Move to... * pthread_rwlock_wrlock.c: ...here. * sysdeps/pthread/pthread_spin_destroy.c: Move to... * pthread_spin_destroy.c: ...here. * sysdeps/pthread/pthread_spin_init.c: Move to... * pthread_spin_init.c: ...here. * sysdeps/pthread/pthread_spin_unlock.c: Move to... * pthread_spin_unlock.c: ...here. * sysdeps/pthread/pthread_getcpuclockid.c: Move to... * pthread_getcpuclockid.c: ...here.
Diffstat (limited to 'nptl/pthread_cond_wait.c')
-rw-r--r--nptl/pthread_cond_wait.c191
1 files changed, 191 insertions, 0 deletions
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
new file mode 100644
index 0000000000..f5f5cec5a8
--- /dev/null
+++ b/nptl/pthread_cond_wait.c
@@ -0,0 +1,191 @@
+/* Copyright (C) 2003, 2004, 2006 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 <endian.h>
+#include <errno.h>
+#include <sysdep.h>
+#include <lowlevellock.h>
+#include <pthread.h>
+#include <pthreadP.h>
+
+#include <shlib-compat.h>
+
+
+struct _condvar_cleanup_buffer
+{
+ int oldtype;
+ pthread_cond_t *cond;
+ pthread_mutex_t *mutex;
+ unsigned int bc_seq;
+};
+
+
+void
+__attribute__ ((visibility ("hidden")))
+__condvar_cleanup (void *arg)
+{
+ struct _condvar_cleanup_buffer *cbuffer =
+ (struct _condvar_cleanup_buffer *) arg;
+ unsigned int destroying;
+
+ /* We are going to modify shared data. */
+ lll_mutex_lock (cbuffer->cond->__data.__lock);
+
+ if (cbuffer->bc_seq == cbuffer->cond->__data.__broadcast_seq)
+ {
+ /* This thread is not waiting anymore. Adjust the sequence counters
+ appropriately. We do not increment WAKEUP_SEQ if this would
+ bump it over the value of TOTAL_SEQ. This can happen if a thread
+ was woken and then canceled. */
+ if (cbuffer->cond->__data.__wakeup_seq
+ < cbuffer->cond->__data.__total_seq)
+ {
+ ++cbuffer->cond->__data.__wakeup_seq;
+ ++cbuffer->cond->__data.__futex;
+ }
+ ++cbuffer->cond->__data.__woken_seq;
+ }
+
+ cbuffer->cond->__data.__nwaiters -= 1 << COND_CLOCK_BITS;
+
+ /* If pthread_cond_destroy was called on this variable already,
+ notify the pthread_cond_destroy caller all waiters have left
+ and it can be successfully destroyed. */
+ destroying = 0;
+ if (cbuffer->cond->__data.__total_seq == -1ULL
+ && cbuffer->cond->__data.__nwaiters < (1 << COND_CLOCK_BITS))
+ {
+ lll_futex_wake (&cbuffer->cond->__data.__nwaiters, 1);
+ destroying = 1;
+ }
+
+ /* We are done. */
+ lll_mutex_unlock (cbuffer->cond->__data.__lock);
+
+ /* Wake everybody to make sure no condvar signal gets lost. */
+ if (! destroying)
+ lll_futex_wake (&cbuffer->cond->__data.__futex, INT_MAX);
+
+ /* Get the mutex before returning unless asynchronous cancellation
+ is in effect. */
+ __pthread_mutex_cond_lock (cbuffer->mutex);
+}
+
+
+int
+__pthread_cond_wait (cond, mutex)
+ pthread_cond_t *cond;
+ pthread_mutex_t *mutex;
+{
+ struct _pthread_cleanup_buffer buffer;
+ struct _condvar_cleanup_buffer cbuffer;
+ int err;
+
+ /* Make sure we are along. */
+ lll_mutex_lock (cond->__data.__lock);
+
+ /* Now we can release the mutex. */
+ err = __pthread_mutex_unlock_usercnt (mutex, 0);
+ if (__builtin_expect (err, 0))
+ {
+ lll_mutex_unlock (cond->__data.__lock);
+ return err;
+ }
+
+ /* We have one new user of the condvar. */
+ ++cond->__data.__total_seq;
+ ++cond->__data.__futex;
+ cond->__data.__nwaiters += 1 << COND_CLOCK_BITS;
+
+ /* Remember the mutex we are using here. If there is already a
+ different address store this is a bad user bug. Do not store
+ anything for pshared condvars. */
+ if (cond->__data.__mutex != (void *) ~0l)
+ cond->__data.__mutex = mutex;
+
+ /* Prepare structure passed to cancellation handler. */
+ cbuffer.cond = cond;
+ cbuffer.mutex = mutex;
+
+ /* Before we block we enable cancellation. Therefore we have to
+ install a cancellation handler. */
+ __pthread_cleanup_push (&buffer, __condvar_cleanup, &cbuffer);
+
+ /* The current values of the wakeup counter. The "woken" counter
+ must exceed this value. */
+ unsigned long long int val;
+ unsigned long long int seq;
+ val = seq = cond->__data.__wakeup_seq;
+ /* Remember the broadcast counter. */
+ cbuffer.bc_seq = cond->__data.__broadcast_seq;
+
+ do
+ {
+ unsigned int futex_val = cond->__data.__futex;
+
+ /* Prepare to wait. Release the condvar futex. */
+ lll_mutex_unlock (cond->__data.__lock);
+
+ /* Enable asynchronous cancellation. Required by the standard. */
+ cbuffer.oldtype = __pthread_enable_asynccancel ();
+
+ /* Wait until woken by signal or broadcast. */
+ lll_futex_wait (&cond->__data.__futex, futex_val);
+
+ /* Disable asynchronous cancellation. */
+ __pthread_disable_asynccancel (cbuffer.oldtype);
+
+ /* We are going to look at shared data again, so get the lock. */
+ lll_mutex_lock (cond->__data.__lock);
+
+ /* If a broadcast happened, we are done. */
+ if (cbuffer.bc_seq != cond->__data.__broadcast_seq)
+ goto bc_out;
+
+ /* Check whether we are eligible for wakeup. */
+ val = cond->__data.__wakeup_seq;
+ }
+ while (val == seq || cond->__data.__woken_seq == val);
+
+ /* Another thread woken up. */
+ ++cond->__data.__woken_seq;
+
+ bc_out:
+
+ cond->__data.__nwaiters -= 1 << COND_CLOCK_BITS;
+
+ /* If pthread_cond_destroy was called on this varaible already,
+ notify the pthread_cond_destroy caller all waiters have left
+ and it can be successfully destroyed. */
+ if (cond->__data.__total_seq == -1ULL
+ && cond->__data.__nwaiters < (1 << COND_CLOCK_BITS))
+ lll_futex_wake (&cond->__data.__nwaiters, 1);
+
+ /* We are done with the condvar. */
+ lll_mutex_unlock (cond->__data.__lock);
+
+ /* The cancellation handling is back to normal, remove the handler. */
+ __pthread_cleanup_pop (&buffer, 0);
+
+ /* Get the mutex before returning. */
+ return __pthread_mutex_cond_lock (mutex);
+}
+
+versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
+ GLIBC_2_3_2);