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/* Copyright (c) 2014, Linaro Limited
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <stdbool.h>
#include <odp/atomic.h>
#include <odp_atomic_internal.h>
#include <odp/rwlock.h>
#include <odp_spin_internal.h>
void odp_rwlock_init(odp_rwlock_t *rwlock)
{
odp_atomic_init_u32(&rwlock->cnt, 0);
}
void odp_rwlock_read_lock(odp_rwlock_t *rwlock)
{
uint32_t cnt;
int is_locked = 0;
while (is_locked == 0) {
cnt = _odp_atomic_u32_load_mm(&rwlock->cnt, _ODP_MEMMODEL_RLX);
/* waiting for read lock */
if ((int32_t)cnt < 0) {
odp_spin();
continue;
}
is_locked = _odp_atomic_u32_cmp_xchg_strong_mm(&rwlock->cnt,
&cnt,
cnt + 1,
_ODP_MEMMODEL_ACQ,
_ODP_MEMMODEL_RLX);
}
}
void odp_rwlock_read_unlock(odp_rwlock_t *rwlock)
{
_odp_atomic_u32_sub_mm(&rwlock->cnt, 1, _ODP_MEMMODEL_RLS);
}
void odp_rwlock_write_lock(odp_rwlock_t *rwlock)
{
uint32_t cnt;
int is_locked = 0;
while (is_locked == 0) {
uint32_t zero = 0;
cnt = _odp_atomic_u32_load_mm(&rwlock->cnt, _ODP_MEMMODEL_RLX);
/* lock acquired, wait */
if (cnt != 0) {
odp_spin();
continue;
}
is_locked = _odp_atomic_u32_cmp_xchg_strong_mm(&rwlock->cnt,
&zero,
(uint32_t)-1,
_ODP_MEMMODEL_ACQ,
_ODP_MEMMODEL_RLX);
}
}
void odp_rwlock_write_unlock(odp_rwlock_t *rwlock)
{
_odp_atomic_u32_store_mm(&rwlock->cnt, 0, _ODP_MEMMODEL_RLS);
}
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