/* * 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 , * Herb Wartens , * Jim Garlick * 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 #include #include /* * 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 */