// SPDX-License-Identifier: GPL-2.0-only
#ifndef _LINUX_RWBASE_RT_H
#define _LINUX_RWBASE_RT_H

#include <linux/rtmutex.h>
#include <linux/atomic.h>

#define READER_BIAS             (1U << 31)
#define WRITER_BIAS             (1U << 30)

struct rwbase_rt {
        atomic_t                readers;
        struct rt_mutex_base    rtmutex;
};

#define __RWBASE_INITIALIZER(name)                              \
{                                                               \
        .readers = ATOMIC_INIT(READER_BIAS),                    \
        .rtmutex = __RT_MUTEX_BASE_INITIALIZER(name.rtmutex),   \
}

#define init_rwbase_rt(rwbase)                                  \
        do {                                                    \
                rt_mutex_base_init(&(rwbase)->rtmutex);         \
                atomic_set(&(rwbase)->readers, READER_BIAS);    \
        } while (0)


static __always_inline bool rw_base_is_locked(const struct rwbase_rt *rwb)
{
        return atomic_read(&rwb->readers) != READER_BIAS;
}

static __always_inline bool rw_base_is_write_locked(const struct rwbase_rt *rwb)
{
        return atomic_read(&rwb->readers) == WRITER_BIAS;
}

static __always_inline bool rw_base_is_contended(const struct rwbase_rt *rwb)
{
        return atomic_read(&rwb->readers) > 0;
}

#endif /* _LINUX_RWBASE_RT_H */