/*
** Copyright 2002/03, Thomas Kurschel. All rights reserved.
** Distributed under the terms of the MIT License.
*/

/*
        Part of Open SCSI bus manager

        Special locks

        The only one defined herein is a spinlock that automatically
        disabled IRQs on enter and restores them on leave. Probably,
        this should be made public as it's quite basic.
*/

#ifndef __SCSI_LOCK_H__
#define __SCSI_LOCK_H__

#include <KernelExport.h>


// enhanced spinlock that automatically disables irqs when lock is hold
typedef struct spinlock_irq {
        spinlock        lock;                           // normal spinlock
        cpu_status      prev_irq_state;         // irq state before spinlock was entered
} spinlock_irq;


static inline void
spinlock_irq_init(spinlock_irq *lock)
{
        B_INITIALIZE_SPINLOCK(&lock->lock);
}

static inline void
acquire_spinlock_irq(spinlock_irq *lock)
{
        cpu_status prev_irq_state = disable_interrupts();

        acquire_spinlock(&lock->lock);
        lock->prev_irq_state = prev_irq_state;
}

static inline void
release_spinlock_irq(spinlock_irq *lock)
{
        cpu_status prev_irq_state = lock->prev_irq_state;

        release_spinlock(&lock->lock);
        restore_interrupts(prev_irq_state);
}

#endif