forked from Minki/linux
304a0d699a
Implement atomic logic ops -- atomic_{or,xor,and}.
These will replace the atomic_{set,clear}_mask functions that are
available on some archs.
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
183 lines
3.9 KiB
C
183 lines
3.9 KiB
C
/*
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* atomic32.c: 32-bit atomic_t implementation
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*
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* Copyright (C) 2004 Keith M Wesolowski
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* Copyright (C) 2007 Kyle McMartin
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*
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* Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf
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*/
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#include <linux/atomic.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#ifdef CONFIG_SMP
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#define ATOMIC_HASH_SIZE 4
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#define ATOMIC_HASH(a) (&__atomic_hash[(((unsigned long)a)>>8) & (ATOMIC_HASH_SIZE-1)])
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spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
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[0 ... (ATOMIC_HASH_SIZE-1)] = __SPIN_LOCK_UNLOCKED(__atomic_hash)
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};
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#else /* SMP */
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static DEFINE_SPINLOCK(dummy);
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#define ATOMIC_HASH_SIZE 1
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#define ATOMIC_HASH(a) (&dummy)
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#endif /* SMP */
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#define ATOMIC_OP_RETURN(op, c_op) \
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int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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int ret; \
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unsigned long flags; \
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spin_lock_irqsave(ATOMIC_HASH(v), flags); \
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\
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ret = (v->counter c_op i); \
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\
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spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \
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return ret; \
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} \
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EXPORT_SYMBOL(atomic_##op##_return);
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#define ATOMIC_OP(op, c_op) \
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void atomic_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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spin_lock_irqsave(ATOMIC_HASH(v), flags); \
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\
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v->counter c_op i; \
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\
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spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \
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} \
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EXPORT_SYMBOL(atomic_##op);
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ATOMIC_OP_RETURN(add, +=)
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ATOMIC_OP(and, &=)
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ATOMIC_OP(or, |=)
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ATOMIC_OP(xor, ^=)
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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int atomic_xchg(atomic_t *v, int new)
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{
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int ret;
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unsigned long flags;
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spin_lock_irqsave(ATOMIC_HASH(v), flags);
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ret = v->counter;
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v->counter = new;
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spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
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return ret;
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}
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EXPORT_SYMBOL(atomic_xchg);
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int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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int ret;
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unsigned long flags;
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spin_lock_irqsave(ATOMIC_HASH(v), flags);
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ret = v->counter;
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if (likely(ret == old))
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v->counter = new;
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spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
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return ret;
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}
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EXPORT_SYMBOL(atomic_cmpxchg);
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int __atomic_add_unless(atomic_t *v, int a, int u)
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{
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int ret;
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unsigned long flags;
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spin_lock_irqsave(ATOMIC_HASH(v), flags);
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ret = v->counter;
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if (ret != u)
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v->counter += a;
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spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
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return ret;
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}
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EXPORT_SYMBOL(__atomic_add_unless);
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/* Atomic operations are already serializing */
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void atomic_set(atomic_t *v, int i)
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{
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unsigned long flags;
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spin_lock_irqsave(ATOMIC_HASH(v), flags);
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v->counter = i;
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spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
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}
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EXPORT_SYMBOL(atomic_set);
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unsigned long ___set_bit(unsigned long *addr, unsigned long mask)
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{
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unsigned long old, flags;
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spin_lock_irqsave(ATOMIC_HASH(addr), flags);
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old = *addr;
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*addr = old | mask;
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spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
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return old & mask;
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}
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EXPORT_SYMBOL(___set_bit);
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unsigned long ___clear_bit(unsigned long *addr, unsigned long mask)
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{
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unsigned long old, flags;
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spin_lock_irqsave(ATOMIC_HASH(addr), flags);
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old = *addr;
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*addr = old & ~mask;
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spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
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return old & mask;
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}
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EXPORT_SYMBOL(___clear_bit);
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unsigned long ___change_bit(unsigned long *addr, unsigned long mask)
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{
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unsigned long old, flags;
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spin_lock_irqsave(ATOMIC_HASH(addr), flags);
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old = *addr;
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*addr = old ^ mask;
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spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
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return old & mask;
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}
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EXPORT_SYMBOL(___change_bit);
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unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new)
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{
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unsigned long flags;
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u32 prev;
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spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
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if ((prev = *ptr) == old)
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*ptr = new;
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spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
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return (unsigned long)prev;
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}
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EXPORT_SYMBOL(__cmpxchg_u32);
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unsigned long __xchg_u32(volatile u32 *ptr, u32 new)
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{
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unsigned long flags;
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u32 prev;
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spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
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prev = *ptr;
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*ptr = new;
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spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
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return (unsigned long)prev;
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}
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EXPORT_SYMBOL(__xchg_u32);
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