f3d46f9d31
In preparation for removing volatile from the atomic_t definition, this patch adds a volatile cast to all the atomic read functions. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
74 lines
2 KiB
C
74 lines
2 KiB
C
#ifndef __ASM_SH_ATOMIC_H
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#define __ASM_SH_ATOMIC_H
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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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*/
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/system.h>
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#define ATOMIC_INIT(i) ( (atomic_t) { (i) } )
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#define atomic_read(v) (*(volatile int *)&(v)->counter)
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#define atomic_set(v,i) ((v)->counter = (i))
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#if defined(CONFIG_GUSA_RB)
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#include <asm/atomic-grb.h>
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#elif defined(CONFIG_CPU_SH4A)
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#include <asm/atomic-llsc.h>
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#else
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#include <asm/atomic-irq.h>
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#endif
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#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
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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_inc_and_test(v) (atomic_inc_return(v) == 0)
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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_not_zero(v) atomic_add_unless((v), 1, 0)
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#define atomic_inc(v) atomic_add(1, (v))
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#define atomic_dec(v) atomic_sub(1, (v))
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#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
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#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
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/**
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* atomic_add_unless - add unless the number is a given value
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* @v: pointer of type atomic_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as it was not @u.
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* Returns non-zero if @v was not @u, and zero otherwise.
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*/
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static inline int atomic_add_unless(atomic_t *v, int a, int u)
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{
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int c, old;
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c = atomic_read(v);
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for (;;) {
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if (unlikely(c == (u)))
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break;
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old = atomic_cmpxchg((v), c, c + (a));
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if (likely(old == c))
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break;
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c = old;
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}
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return c != (u);
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}
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#define smp_mb__before_atomic_dec() smp_mb()
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#define smp_mb__after_atomic_dec() smp_mb()
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#define smp_mb__before_atomic_inc() smp_mb()
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#define smp_mb__after_atomic_inc() smp_mb()
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#include <asm-generic/atomic-long.h>
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#include <asm-generic/atomic64.h>
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#endif /* __ASM_SH_ATOMIC_H */
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