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/*
* 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
#include <linux/module.h>
#include <linux/spinlock.h>
#include <sys/types.h>
/*
* 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 */
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