mirror_zfs/include/sys/atomic.h

/*
 *  This file is part of the SPL: Solaris Porting Layer.
 *
 *  Copyright (c) 2008 Lawrence Livermore National Security, LLC.
 *  Produced at Lawrence Livermore National Laboratory
 *  Written by:
 *          Brian Behlendorf <behlendorf1@llnl.gov>,
 *          Herb Wartens <wartens2@llnl.gov>,
 *          Jim Garlick <garlick@llnl.gov>
 *  UCRL-CODE-235197
 *
 *  This is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This is distributed in the hope that it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
 */

#ifndef _SPL_ATOMIC_H
#define _SPL_ATOMIC_H

#ifdef  __cplusplus
extern "C" {
#endif

#include <linux/module.h>
#include <linux/spinlock.h>

/* XXX: Serialize everything through global locks.  This is
 * going to be bad for performance, but for now it's the easiest
 * way to ensure correct behavior.  I don't like it at all.
 * It would be nicer to make these function to the atomic linux
 * functions, but the normal uint64_t type complicates this.
 */
extern spinlock_t atomic64_lock;
extern spinlock_t atomic32_lock;

static __inline__ uint32_t
atomic_add_32(volatile uint32_t *target, int32_t delta)
{
	uint32_t rc;

	spin_lock(&atomic32_lock);
	rc = *target;
	*target += delta;
	spin_unlock(&atomic32_lock);

	return rc;
}

static __inline__ void
atomic_inc_64(volatile uint64_t *target)
{
	spin_lock(&atomic64_lock);
	(*target)++;
	spin_unlock(&atomic64_lock);
}

static __inline__ void
atomic_dec_64(volatile uint64_t *target)
{
	spin_lock(&atomic64_lock);
	(*target)--;
	spin_unlock(&atomic64_lock);
}

static __inline__ uint64_t
atomic_add_64(volatile uint64_t *target, uint64_t delta)
{
	uint64_t rc;

	spin_lock(&atomic64_lock);
	rc = *target;
	*target += delta;
	spin_unlock(&atomic64_lock);

	return rc;
}

static __inline__ uint64_t
atomic_sub_64(volatile uint64_t *target, uint64_t delta)
{
	uint64_t rc;

	spin_lock(&atomic64_lock);
	rc = *target;
	*target -= delta;
	spin_unlock(&atomic64_lock);

	return rc;
}

static __inline__ uint64_t
atomic_add_64_nv(volatile uint64_t *target, uint64_t delta)
{
	spin_lock(&atomic64_lock);
	*target += delta;
	spin_unlock(&atomic64_lock);

	return *target;
}

static __inline__ uint64_t
atomic_sub_64_nv(volatile uint64_t *target, uint64_t delta)
{
	spin_lock(&atomic64_lock);
	*target -= delta;
	spin_unlock(&atomic64_lock);

	return *target;
}

static __inline__ uint64_t
atomic_cas_64(volatile uint64_t *target,  uint64_t cmp,
               uint64_t newval)
{
	uint64_t rc;

	spin_lock(&atomic64_lock);
	rc = *target;
	if (*target == cmp)
		*target = newval;
	spin_unlock(&atomic64_lock);

	return rc;
}

#if defined(__x86_64__)
/* XXX: Implement atomic_cas_ptr() in terms of uint64'ts.  This
 * is of course only safe and correct for 64 bit arches...  but
 * for now I'm OK with that.
 */
static __inline__ void *
atomic_cas_ptr(volatile void *target,  void *cmp, void *newval)
{
	return (void *)atomic_cas_64((volatile uint64_t *)target,
	                             (uint64_t)cmp, (uint64_t)newval);
}
#endif

#ifdef  __cplusplus
}
#endif

#endif  /* _SPL_ATOMIC_H */