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/* Copyright (c) 2013, Linaro Limited
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/**
* @file
*
* ODP ticketlock
*/
#ifndef ODP_TICKETLOCK_H_
#define ODP_TICKETLOCK_H_
#ifdef __cplusplus
extern "C" {
#endif
#include <odp_std_types.h>
#include <odp_atomic.h>
/** @addtogroup odp_synchronizers
* Operations on ticket locks.
* Acquiring a ticket lock happens in two phases. First the threads takes a
* ticket. Second it waits (spins) until it is its turn.
* Ticket locks are believed to be more fair than spin locks.
* Ticket locks shall not be used in the presence of preemption.
* @{
*/
/**
* ODP ticket lock
*/
typedef struct odp_ticketlock_t {
odp_atomic_u32_t next_ticket; /**< @private Next ticket */
odp_atomic_u32_t cur_ticket; /**< @private Current ticket */
} odp_ticketlock_t;
/**
* Initialize ticket lock.
*
* @param tklock Pointer to a ticket lock
*/
void odp_ticketlock_init(odp_ticketlock_t *tklock);
/**
* Acquire ticket lock.
*
* @param tklock Pointer to a ticket lock
*/
void odp_ticketlock_lock(odp_ticketlock_t *tklock);
/**
* Try to acquire ticket lock.
*
* @param tklock Pointer to a ticket lock
*
* @retval 1 lock acquired
* @retval 0 lock not acquired
*/
int odp_ticketlock_trylock(odp_ticketlock_t *tklock);
/**
* Release ticket lock.
*
* @param tklock Pointer to a ticket lock
*/
void odp_ticketlock_unlock(odp_ticketlock_t *tklock);
/**
* Check if ticket lock is locked.
*
* @param tklock Pointer to a ticket lock
*
* @retval 1 the lock is busy (locked)
* @retval 0 the lock is available (unlocked)
*/
int odp_ticketlock_is_locked(odp_ticketlock_t *tklock);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#endif
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