mirror_zfs/include/sys/atomic.h
Brian Behlendorf 716154c592 Public Release Prep
Updated AUTHORS, COPYING, DISCLAIMER, and INSTALL files.  Added
standardized headers to all source file to clearly indicate the
copyright, license, and to give credit where credit is due.
2010-05-17 15:18:00 -07:00

233 lines
6.3 KiB
C

/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://github.com/behlendorf/spl/>.
*
* The SPL 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.
*
* The SPL 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 the SPL. If not, see <http://www.gnu.org/licenses/>.
\*****************************************************************************/
#ifndef _SPL_ATOMIC_H
#define _SPL_ATOMIC_H
#include <linux/module.h>
#include <linux/spinlock.h>
#include <sys/types.h>
#ifndef HAVE_ATOMIC64_CMPXCHG
#define atomic64_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
#endif
#ifndef HAVE_ATOMIC64_XCHG
#define atomic64_xchg(v, n) (xchg(&((v)->counter), n))
#endif
/*
* Two approaches to atomic operations are implemented each with its
* own benefits are drawbacks imposed by the Solaris API. Neither
* approach handles the issue of word breaking when using a 64-bit
* atomic variable on a 32-bit arch. The Solaris API would need to
* add an atomic read call to correctly support this.
*
* When ATOMIC_SPINLOCK is defined all atomic operations will be
* serialized through global spin locks. This is bad for performance
* but it does allow a simple generic implementation.
*
* When ATOMIC_SPINLOCK is not defined the Linux atomic operations
* are used. This is safe as long as the core Linux implementation
* doesn't change because we are relying on the fact that an atomic
* type is really just a uint32 or uint64. If this changes at some
* point in the future we need to fall-back to the spin approach.
*/
#ifdef ATOMIC_SPINLOCK
extern spinlock_t atomic32_lock;
extern spinlock_t atomic64_lock;
static __inline__ void
atomic_inc_32(volatile uint32_t *target)
{
spin_lock(&atomic32_lock);
(*target)++;
spin_unlock(&atomic32_lock);
}
static __inline__ void
atomic_dec_32(volatile uint32_t *target)
{
spin_lock(&atomic32_lock);
(*target)--;
spin_unlock(&atomic32_lock);
}
static __inline__ void
atomic_add_32(volatile uint32_t *target, int32_t delta)
{
spin_lock(&atomic32_lock);
*target += delta;
spin_unlock(&atomic32_lock);
}
static __inline__ void
atomic_sub_32(volatile uint32_t *target, int32_t delta)
{
spin_lock(&atomic32_lock);
*target -= delta;
spin_unlock(&atomic32_lock);
}
static __inline__ uint32_t
atomic_add_32_nv(volatile uint32_t *target, uint32_t delta)
{
spin_lock(&atomic32_lock);
*target += delta;
spin_unlock(&atomic32_lock);
return *target;
}
static __inline__ uint32_t
atomic_sub_32_nv(volatile uint32_t *target, uint32_t delta)
{
spin_lock(&atomic32_lock);
*target -= delta;
spin_unlock(&atomic32_lock);
return *target;
}
static __inline__ uint32_t
atomic_cas_32(volatile uint32_t *target, uint32_t cmp,
uint32_t newval)
{
uint32_t rc;
spin_lock(&atomic32_lock);
rc = *target;
if (*target == cmp)
*target = newval;
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__ void
atomic_add_64(volatile uint64_t *target, uint64_t delta)
{
spin_lock(&atomic64_lock);
*target += delta;
spin_unlock(&atomic64_lock);
}
static __inline__ void
atomic_sub_64(volatile uint64_t *target, uint64_t delta)
{
spin_lock(&atomic64_lock);
*target -= delta;
spin_unlock(&atomic64_lock);
}
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;
}
#else /* ATOMIC_SPINLOCK */
#define atomic_inc_32(v) atomic_inc((atomic_t *)(v))
#define atomic_dec_32(v) atomic_dec((atomic_t *)(v))
#define atomic_add_32(v, i) atomic_add((i), (atomic_t *)(v))
#define atomic_sub_32(v, i) atomic_sub((i), (atomic_t *)(v))
#define atomic_add_32_nv(v, i) atomic_add_return((i), (atomic_t *)(v))
#define atomic_sub_32_nv(v, i) atomic_sub_return((i), (atomic_t *)(v))
#define atomic_cas_32(v, x, y) atomic_cmpxchg((atomic_t *)(v), x, y)
#define atomic_inc_64(v) atomic64_inc((atomic64_t *)(v))
#define atomic_dec_64(v) atomic64_dec((atomic64_t *)(v))
#define atomic_add_64(v, i) atomic64_add((i), (atomic64_t *)(v))
#define atomic_sub_64(v, i) atomic64_sub((i), (atomic64_t *)(v))
#define atomic_add_64_nv(v, i) atomic64_add_return((i), (atomic64_t *)(v))
#define atomic_sub_64_nv(v, i) atomic64_sub_return((i), (atomic64_t *)(v))
#define atomic_cas_64(v, x, y) atomic64_cmpxchg((atomic64_t *)(v), x, y)
#endif /* ATOMIC_SPINLOCK */
#ifdef _LP64
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);
}
#else /* _LP64 */
static __inline__ void *
atomic_cas_ptr(volatile void *target, void *cmp, void *newval)
{
return (void *)atomic_cas_32((volatile uint32_t *)target,
(uint32_t)cmp, (uint32_t)newval);
}
#endif /* _LP64 */
#endif /* _SPL_ATOMIC_H */