162 lines
3.7 KiB
C
162 lines
3.7 KiB
C
/*
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* Generic C implementation of atomic counter operations
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* Originally implemented for MN10300.
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef __ASM_GENERIC_ATOMIC_H
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#define __ASM_GENERIC_ATOMIC_H
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#ifdef CONFIG_SMP
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#error not SMP safe
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#endif
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#define ATOMIC_INIT(i) { (i) }
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#ifdef __KERNEL__
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/**
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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#define atomic_read(v) (*(volatile int *)&(v)->counter)
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/**
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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#define atomic_set(v, i) (((v)->counter) = (i))
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#include <asm/system.h>
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/**
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* atomic_add_return - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v and returns the result
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*/
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static inline int atomic_add_return(int i, atomic_t *v)
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{
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unsigned long flags;
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int temp;
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local_irq_save(flags);
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temp = v->counter;
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temp += i;
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v->counter = temp;
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local_irq_restore(flags);
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return temp;
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}
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/**
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* atomic_sub_return - subtract integer from atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns the result
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*/
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static inline int atomic_sub_return(int i, atomic_t *v)
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{
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unsigned long flags;
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int temp;
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local_irq_save(flags);
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temp = v->counter;
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temp -= i;
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v->counter = temp;
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local_irq_restore(flags);
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return temp;
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}
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static inline int atomic_add_negative(int i, atomic_t *v)
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{
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return atomic_add_return(i, v) < 0;
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}
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static inline void atomic_add(int i, atomic_t *v)
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{
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atomic_add_return(i, v);
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}
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static inline void atomic_sub(int i, atomic_t *v)
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{
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atomic_sub_return(i, v);
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}
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static inline void atomic_inc(atomic_t *v)
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{
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atomic_add_return(1, v);
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}
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static inline void atomic_dec(atomic_t *v)
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{
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atomic_sub_return(1, v);
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}
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#define atomic_dec_return(v) atomic_sub_return(1, (v))
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#define atomic_inc_return(v) atomic_add_return(1, (v))
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#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
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#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
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#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
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#define atomic_add_unless(v, a, u) \
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({ \
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int c, old; \
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c = atomic_read(v); \
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while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
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c = old; \
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c != (u); \
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})
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
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{
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unsigned long flags;
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mask = ~mask;
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local_irq_save(flags);
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*addr &= mask;
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local_irq_restore(flags);
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}
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#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
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#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
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#define cmpxchg_local(ptr, o, n) \
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((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
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(unsigned long)(n), sizeof(*(ptr))))
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#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
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/* Assume that atomic operations are already serializing */
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#define smp_mb__before_atomic_dec() barrier()
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#define smp_mb__after_atomic_dec() barrier()
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#define smp_mb__before_atomic_inc() barrier()
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#define smp_mb__after_atomic_inc() barrier()
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#include <asm-generic/atomic-long.h>
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#endif /* __KERNEL__ */
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#endif /* __ASM_GENERIC_ATOMIC_H */
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