/*
 * Copyright 2022, Haiku, Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 */
#ifndef _OBSD_COMPAT_SYS_RWLOCK_H_
#define _OBSD_COMPAT_SYS_RWLOCK_H_


#include <sys/mutex.h>


struct rwlock_openbsd {
        struct rw_lock lock;
};
#define rwlock rwlock_openbsd


static inline void
rw_init_flags(struct rwlock* rwl, const char* name, int flags)
{
        rw_lock_init(&rwl->lock, name);
}
#define rw_init(rwl, name)      rw_init_flags(rwl, name, 0)


#define RW_WRITE                0x0001UL
#define RW_READ                 0x0002UL
#define RW_OPMASK               0x0007UL

#define RW_INTR                 0x0010UL


static int
rw_enter(struct rwlock* rwl, int flags)
{
        const int op = (flags & RW_OPMASK);
        const int giant = mtx_owned(&Giant);
        if (giant)
                mtx_unlock(&Giant);

        int status;
        if (op == RW_WRITE)
                status = rw_lock_write_lock(&rwl->lock);
        else if (op == RW_READ)
                status = rw_lock_read_lock(&rwl->lock);
        else
                panic("bad rw op");

        if (giant)
                mtx_lock(&Giant);
        return status;
}

static inline int
rw_enter_write(struct rwlock* rwl)
{
        return rw_enter(rwl, RW_WRITE);
}

static inline void
rw_exit_write(struct rwlock* rwl)
{
        rw_lock_write_unlock(&rwl->lock);
}

static inline void
rw_exit(struct rwlock* rwl)
{
        if (rwl->lock.holder == find_thread(NULL))
                rw_lock_write_unlock(&rwl->lock);
        else
                rw_lock_read_unlock(&rwl->lock);
}

static inline void
rw_assert_wrlock(struct rwlock* rwl)
{
#if KDEBUG
        if (rwl->lock.holder != find_thread(NULL))
                panic("rw_assert_wrlock failed!");
#endif
}


#endif  /* _OBSD_COMPAT_SYS_RWLOCK_H_ */