mirror of
https://github.com/apache/nuttx.git
synced 2026-05-22 13:52:22 +08:00
pthreads: Adding rwlock implementation
Adding an implementation for read/write locks into the pthread library. These locks are writer priority, such that if any writers come in they are given priority for writing.
This commit is contained in:
Mark Schulte
committed by
Gregory Nutt
Gregory Nutt
parent
58d0c1f228
commit
7bb26d2615
+41
-2
@@ -337,6 +337,28 @@ typedef struct pthread_barrier_s pthread_barrier_t;
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typedef bool pthread_once_t;
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#define __PTHREAD_ONCE_T_DEFINED 1
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#ifdef CONFIG_PTHREAD_RWLOCK
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struct pthread_rwlock_s
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{
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pthread_mutex_t lock;
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pthread_cond_t cv;
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unsigned int num_readers;
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unsigned int num_writers;
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};
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typedef struct pthread_rwlock_s pthread_rwlock_t;
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typedef int pthread_rwlockattr_t;
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#define PTHREAD_RWLOCK_INITIALIZER {PTHREAD_MUTEX_INITIALIZER, \
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PTHREAD_COND_INITIALIZER, \
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0, 0}
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#define PTHREAD_MUTEX_INITIALIZER {NULL, SEM_INITIALIZER(1), -1, \
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__PTHREAD_MUTEX_DEFAULT_FLAGS, \
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PTHREAD_MUTEX_DEFAULT, 0}
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#endif
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#ifdef CONFIG_PTHREAD_CLEANUP
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/* This type describes the pthread cleanup callback (non-standard) */
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@@ -539,8 +561,8 @@ int pthread_barrierattr_setpshared(FAR pthread_barrierattr_t *attr,
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int pthread_barrier_destroy(FAR pthread_barrier_t *barrier);
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int pthread_barrier_init(FAR pthread_barrier_t *barrier,
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FAR const pthread_barrierattr_t *attr,
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unsigned int count);
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FAR const pthread_barrierattr_t *attr,
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unsigned int count);
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int pthread_barrier_wait(FAR pthread_barrier_t *barrier);
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/* Pthread initialization */
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@@ -548,6 +570,23 @@ int pthread_barrier_wait(FAR pthread_barrier_t *barrier);
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int pthread_once(FAR pthread_once_t *once_control,
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CODE void (*init_routine)(void));
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/* Pthread rwlock */
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#ifdef CONFIG_PTHREAD_RWLOCK
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int pthread_rwlock_destroy(FAR pthread_rwlock_t *rw_lock);
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int pthread_rwlock_init(FAR pthread_rwlock_t *rw_lock,
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FAR const pthread_rwlockattr_t *attr);
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int pthread_rwlock_rdlock(pthread_rwlock_t *lock);
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int pthread_rwlock_timedrdlock(FAR pthread_rwlock_t *lock,
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FAR const struct timespec *abstime);
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int pthread_rwlock_tryrdlock(FAR pthread_rwlock_t *lock);
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int pthread_rwlock_wrlock(FAR pthread_rwlock_t *lock);
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int pthread_rwlock_timedwrlock(FAR pthread_rwlock_t *lock,
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FAR const struct timespec *abstime);
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int pthread_rwlock_trywrlock(FAR pthread_rwlock_t *lock);
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int pthread_rwlock_unlock(FAR pthread_rwlock_t *lock);
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#endif /* CONFIG_PTHREAD_RWLOCK */
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/* Pthread signal management APIs */
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int pthread_kill(pthread_t thread, int sig);
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@@ -53,6 +53,10 @@ CSRCS += pthread_mutexattr_setrobust.c pthread_mutexattr_getrobust.c
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CSRCS += pthread_setcancelstate.c pthread_setcanceltype.c
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CSRCS += pthread_testcancel.c
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ifeq ($(CONFIG_PTHREAD_RWLOCK),y)
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CSRCS += pthread_rwlock.c pthread_rwlock_rdlock.c pthread_rwlock_wrlock.c
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endif
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ifeq ($(CONFIG_SMP),y)
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CSRCS += pthread_attr_getaffinity.c pthread_attr_setaffinity.c
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endif
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@@ -0,0 +1,127 @@
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/****************************************************************************
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* libc/pthread/pthread_rwlock.c
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*
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* Copyright (C) 2017 Mark Schulte. All rights reserved.
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* Author: Mark Schulte <mark@mjs.pw>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <pthread.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/semaphore.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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int pthread_rwlock_init(FAR pthread_rwlock_t *lock,
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FAR const pthread_rwlockattr_t *attr)
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{
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int err;
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if (attr != NULL)
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{
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return -ENOSYS;
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}
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lock->num_readers = 0;
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lock->num_writers = 0;
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err = pthread_cond_init(&lock->cv, NULL);
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if (err != 0)
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{
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return err;
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}
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err = pthread_mutex_init(&lock->lock, NULL);
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if (err != 0)
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{
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pthread_cond_destroy(&lock->cv);
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return err;
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}
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return err;
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}
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int pthread_rwlock_destroy(FAR pthread_rwlock_t *lock)
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{
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int cond_err = pthread_cond_destroy(&lock->cv);
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int mutex_err = pthread_mutex_destroy(&lock->lock);
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if (mutex_err)
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{
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return mutex_err;
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}
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return cond_err;
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}
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int pthread_rwlock_unlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err;
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err = pthread_mutex_lock(&rw_lock->lock);
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if (err != 0)
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{
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return err;
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}
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if (rw_lock->num_readers > 0)
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{
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rw_lock->num_readers--;
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if (rw_lock->num_readers == 0)
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{
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err = pthread_cond_broadcast(&rw_lock->cv);
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}
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}
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else if (rw_lock->num_writers > 0)
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{
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rw_lock->num_writers--;
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err = pthread_cond_broadcast(&rw_lock->cv);
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}
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else
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{
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err = EINVAL;
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}
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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@@ -0,0 +1,143 @@
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/****************************************************************************
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* libc/pthread/pthread_rwlockread.c
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*
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* Copyright (C) 2017 Mark Schulte. All rights reserved.
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* Author: Mark Schulte <mark@mjs.pw>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <pthread.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/semaphore.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static int tryrdlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err;
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if (rw_lock->num_writers > 0)
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{
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err = EBUSY;
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}
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else if (rw_lock->num_readers == UINT_MAX)
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{
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err = EAGAIN;
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}
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else
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{
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rw_lock->num_readers++;
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err = OK;
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}
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return err;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pthread_rwlock_rdlock
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*
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* Description:
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* Locks a read/write lock for reading
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*
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* Parameters:
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* None
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*
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* Return Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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int pthread_rwlock_tryrdlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err = pthread_mutex_trylock(&rw_lock->lock);
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if (err != 0)
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{
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return err;
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}
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err = tryrdlock(rw_lock);
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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int pthread_rwlock_timedrdlock(FAR pthread_rwlock_t *rw_lock,
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FAR const struct timespec *ts)
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{
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int err = pthread_mutex_lock(&rw_lock->lock);
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if (err != 0)
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{
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return err;
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}
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while ((err = tryrdlock(rw_lock)) == EBUSY)
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{
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if (ts != NULL)
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{
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err = pthread_cond_timedwait(&rw_lock->cv, &rw_lock->lock, ts);
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}
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else
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{
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err = pthread_cond_wait(&rw_lock->cv, &rw_lock->lock);
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}
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if (err != 0)
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{
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break;
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}
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}
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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int pthread_rwlock_rdlock(FAR pthread_rwlock_t * rw_lock)
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{
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return pthread_rwlock_timedrdlock(rw_lock, NULL);
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}
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@@ -0,0 +1,133 @@
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/****************************************************************************
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* libc/pthread/pthread_rwlockwrite.c
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*
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* Copyright (C) 2017 Mark Schulte. All rights reserved.
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* Author: Mark Schulte <mark@mjs.pw>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
|
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* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in
|
||||
* the documentation and/or other materials provided with the
|
||||
* distribution.
|
||||
* 3. Neither the name NuttX nor the names of its contributors may be
|
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* used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
||||
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
||||
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
||||
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <pthread.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/semaphore.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pthread_rwlock_rdlock
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*
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* Description:
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* Locks a read/write lock for reading
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*
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* Parameters:
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* None
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*
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* Return Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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int pthread_rwlock_trywrlock(FAR pthread_rwlock_t *rw_lock)
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{
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int err = pthread_mutex_trylock(&rw_lock->lock);
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if (err != 0)
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{
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return err;
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}
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if (rw_lock->num_readers > 0 || rw_lock->num_writers > 0)
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{
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err = EBUSY;
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}
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else
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{
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rw_lock->num_writers++;
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}
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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int pthread_rwlock_timedwrlock(FAR pthread_rwlock_t *rw_lock,
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FAR const struct timespec *ts)
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{
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int err = pthread_mutex_lock(&rw_lock->lock);
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int num_writers_current;
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if (err != 0)
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{
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return err;
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}
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num_writers_current = rw_lock->num_writers++;
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if (num_writers_current == 0)
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{
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goto exit_with_mutex;
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}
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while (rw_lock->num_writers != num_writers_current)
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{
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if (ts != NULL)
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{
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err = pthread_cond_timedwait(&rw_lock->cv, &rw_lock->lock, ts);
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}
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else
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{
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err = pthread_cond_wait(&rw_lock->cv, &rw_lock->lock);
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}
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if (err != 0)
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{
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break;
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}
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}
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exit_with_mutex:
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pthread_mutex_unlock(&rw_lock->lock);
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return err;
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}
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int pthread_rwlock_wrlock(FAR pthread_rwlock_t *rw_lock)
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{
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return pthread_rwlock_timedwrlock(rw_lock, NULL);
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}
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@@ -573,6 +573,12 @@ config PTHREAD_MUTEX_DEFAULT_UNSAFE
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endchoice # Default NORMAL mutex robustness
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config PTHREAD_RWLOCK
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bool "Enable pthread rwlock API"
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default n
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---help---
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Add supports for the rwlock interfaces
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config NPTHREAD_KEYS
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int "Maximum number of pthread keys"
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default 4
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Block a user