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/* Copyright (c) 2014, Linaro Limited
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef ODP_RWLOCK_H_
#define ODP_RWLOCK_H_
/**
* @file
*
* ODP RW Locks
*/
#include <odp/atomic.h>
#ifdef __cplusplus
extern "C" {
#endif
/** @defgroup odp_synchronizers ODP SYNCRONIZERS
* Operations on reader/writer locks.
* A reader/writer lock allows multiple simultaneous readers but only one
* writer at a time.
* A thread that wants write access will have to wait until there are no
* threads that want read access. This casues a risk for starvation.
* @{
*/
/**
* The odp_rwlock_t type.
*/
typedef struct {
odp_atomic_u32_t cnt; /**< @private lock count
0 lock not taken
-1 write lock taken
>0 read lock(s) taken */
} odp_rwlock_t;
/**
* Initialize a reader/writer lock.
*
* @param rwlock Pointer to a reader/writer lock
*/
void odp_rwlock_init(odp_rwlock_t *rwlock);
/**
* Acquire read permission on a reader/writer lock.
*
* @param rwlock Pointer to a reader/writer lock
*/
void odp_rwlock_read_lock(odp_rwlock_t *rwlock);
/**
* Release read permission on a reader/writer lock.
*
* @param rwlock Pointer to a reader/writer lock
*/
void odp_rwlock_read_unlock(odp_rwlock_t *rwlock);
/**
* Acquire write permission on a reader/writer lock.
*
* @param rwlock Pointer to a reader/writer lock
*/
void odp_rwlock_write_lock(odp_rwlock_t *rwlock);
/**
* Release write permission on a reader/writer lock.
*
* @param rwlock Pointer to a reader/writer lock
*/
void odp_rwlock_write_unlock(odp_rwlock_t *rwlock);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#endif /* ODP_RWLOCK_H_ */
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