rte_seqlock.h

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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2022 Ericsson AB
 */

#ifndef _RTE_SEQLOCK_H_
#define _RTE_SEQLOCK_H_

#include <stdbool.h>
#include <stdint.h>

#include <rte_atomic.h>
#include <rte_branch_prediction.h>
#include <rte_seqcount.h>
#include <rte_spinlock.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
    rte_seqcount_t count; 
    rte_spinlock_t lock; 
} rte_seqlock_t;

#define RTE_SEQLOCK_INITIALIZER \
    {                           \
        .count = RTE_SEQCOUNT_INITIALIZER,      \
        .lock = RTE_SPINLOCK_INITIALIZER        \
    }

static inline void
rte_seqlock_init(rte_seqlock_t *seqlock)
{
    rte_seqcount_init(&seqlock->count);
    rte_spinlock_init(&seqlock->lock);
}

static inline uint32_t
rte_seqlock_read_begin(const rte_seqlock_t *seqlock)
{
    return rte_seqcount_read_begin(&seqlock->count);
}

static inline bool
rte_seqlock_read_retry(const rte_seqlock_t *seqlock, uint32_t begin_sn)
{
    return rte_seqcount_read_retry(&seqlock->count, begin_sn);
}

static inline void
rte_seqlock_write_lock(rte_seqlock_t *seqlock)
    __rte_exclusive_lock_function(&seqlock->lock)
{
    /* To synchronize with other writers. */
    rte_spinlock_lock(&seqlock->lock);

    rte_seqcount_write_begin(&seqlock->count);
}

static inline void
rte_seqlock_write_unlock(rte_seqlock_t *seqlock)
    __rte_unlock_function(&seqlock->lock)
{
    rte_seqcount_write_end(&seqlock->count);

    rte_spinlock_unlock(&seqlock->lock);
}

#ifdef __cplusplus
}
#endif

#endif /* _RTE_SEQLOCK_H_ */