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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_rwlock_wrlock.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_rwlock_wrlock.c')
-rw-r--r--nptl/pthread_rwlock_wrlock.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/nptl/pthread_rwlock_wrlock.c b/nptl/pthread_rwlock_wrlock.c
new file mode 100644
index 0000000000..822aeed79c
--- /dev/null
+++ b/nptl/pthread_rwlock_wrlock.c
@@ -0,0 +1,87 @@
+/* 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. */
+ 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. */
+ 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)