236 lines
		
	
	
		
			5.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			236 lines
		
	
	
		
			5.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef _ASM_X86_LOCAL_H
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#define _ASM_X86_LOCAL_H
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#include <linux/percpu.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <asm/asm.h>
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typedef struct {
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	atomic_long_t a;
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} local_t;
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#define LOCAL_INIT(i)	{ ATOMIC_LONG_INIT(i) }
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#define local_read(l)	atomic_long_read(&(l)->a)
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#define local_set(l, i)	atomic_long_set(&(l)->a, (i))
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static inline void local_inc(local_t *l)
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{
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	asm volatile(_ASM_INC "%0"
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		     : "+m" (l->a.counter));
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}
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static inline void local_dec(local_t *l)
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{
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	asm volatile(_ASM_DEC "%0"
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		     : "+m" (l->a.counter));
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}
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static inline void local_add(long i, local_t *l)
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{
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	asm volatile(_ASM_ADD "%1,%0"
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		     : "+m" (l->a.counter)
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		     : "ir" (i));
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}
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static inline void local_sub(long i, local_t *l)
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{
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	asm volatile(_ASM_SUB "%1,%0"
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		     : "+m" (l->a.counter)
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		     : "ir" (i));
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}
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/**
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 * local_sub_and_test - subtract value from variable and test result
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 * @i: integer value to subtract
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 * @l: pointer to type local_t
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 *
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 * Atomically subtracts @i from @l and returns
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 * true if the result is zero, or false for all
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 * other cases.
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 */
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static inline int local_sub_and_test(long i, local_t *l)
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{
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	unsigned char c;
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	asm volatile(_ASM_SUB "%2,%0; sete %1"
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		     : "+m" (l->a.counter), "=qm" (c)
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		     : "ir" (i) : "memory");
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	return c;
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}
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/**
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 * local_dec_and_test - decrement and test
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 * @l: pointer to type local_t
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 *
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 * Atomically decrements @l by 1 and
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 * returns true if the result is 0, or false for all other
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 * cases.
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 */
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static inline int local_dec_and_test(local_t *l)
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{
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	unsigned char c;
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	asm volatile(_ASM_DEC "%0; sete %1"
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		     : "+m" (l->a.counter), "=qm" (c)
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		     : : "memory");
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	return c != 0;
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}
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/**
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 * local_inc_and_test - increment and test
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 * @l: pointer to type local_t
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 *
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 * Atomically increments @l by 1
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 * and returns true if the result is zero, or false for all
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 * other cases.
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 */
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static inline int local_inc_and_test(local_t *l)
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{
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	unsigned char c;
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	asm volatile(_ASM_INC "%0; sete %1"
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		     : "+m" (l->a.counter), "=qm" (c)
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		     : : "memory");
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	return c != 0;
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}
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/**
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 * local_add_negative - add and test if negative
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 * @i: integer value to add
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 * @l: pointer to type local_t
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 *
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 * Atomically adds @i to @l and returns true
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 * if the result is negative, or false when
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 * result is greater than or equal to zero.
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 */
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static inline int local_add_negative(long i, local_t *l)
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{
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	unsigned char c;
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	asm volatile(_ASM_ADD "%2,%0; sets %1"
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		     : "+m" (l->a.counter), "=qm" (c)
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		     : "ir" (i) : "memory");
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	return c;
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}
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/**
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 * local_add_return - add and return
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 * @i: integer value to add
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 * @l: pointer to type local_t
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 *
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 * Atomically adds @i to @l and returns @i + @l
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 */
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static inline long local_add_return(long i, local_t *l)
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{
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	long __i;
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#ifdef CONFIG_M386
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	unsigned long flags;
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	if (unlikely(boot_cpu_data.x86 <= 3))
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		goto no_xadd;
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#endif
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	/* Modern 486+ processor */
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	__i = i;
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	asm volatile(_ASM_XADD "%0, %1;"
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		     : "+r" (i), "+m" (l->a.counter)
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		     : : "memory");
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	return i + __i;
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#ifdef CONFIG_M386
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no_xadd: /* Legacy 386 processor */
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	local_irq_save(flags);
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	__i = local_read(l);
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	local_set(l, i + __i);
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	local_irq_restore(flags);
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	return i + __i;
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#endif
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}
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static inline long local_sub_return(long i, local_t *l)
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{
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	return local_add_return(-i, l);
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}
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#define local_inc_return(l)  (local_add_return(1, l))
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#define local_dec_return(l)  (local_sub_return(1, l))
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#define local_cmpxchg(l, o, n) \
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	(cmpxchg_local(&((l)->a.counter), (o), (n)))
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/* Always has a lock prefix */
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#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
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/**
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 * local_add_unless - add unless the number is a given value
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 * @l: pointer of type local_t
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 * @a: the amount to add to l...
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 * @u: ...unless l is equal to u.
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 *
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 * Atomically adds @a to @l, so long as it was not @u.
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 * Returns non-zero if @l was not @u, and zero otherwise.
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 */
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#define local_add_unless(l, a, u)				\
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({								\
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	long c, old;						\
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	c = local_read((l));					\
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	for (;;) {						\
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		if (unlikely(c == (u)))				\
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			break;					\
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		old = local_cmpxchg((l), 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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	c != (u);						\
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})
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#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
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/* On x86_32, these are no better than the atomic variants.
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 * On x86-64 these are better than the atomic variants on SMP kernels
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 * because they dont use a lock prefix.
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 */
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#define __local_inc(l)		local_inc(l)
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#define __local_dec(l)		local_dec(l)
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#define __local_add(i, l)	local_add((i), (l))
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#define __local_sub(i, l)	local_sub((i), (l))
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/* Use these for per-cpu local_t variables: on some archs they are
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 * much more efficient than these naive implementations.  Note they take
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 * a variable, not an address.
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 *
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 * X86_64: This could be done better if we moved the per cpu data directly
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 * after GS.
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 */
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/* Need to disable preemption for the cpu local counters otherwise we could
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   still access a variable of a previous CPU in a non atomic way. */
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#define cpu_local_wrap_v(l)		\
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({					\
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	local_t res__;			\
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	preempt_disable(); 		\
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	res__ = (l);			\
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	preempt_enable();		\
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	res__;				\
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})
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#define cpu_local_wrap(l)		\
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({					\
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	preempt_disable();		\
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	(l);				\
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	preempt_enable();		\
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})					\
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#define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var((l))))
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#define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var((l)), (i)))
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#define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var((l))))
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#define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var((l))))
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#define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var((l))))
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#define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var((l))))
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#define __cpu_local_inc(l)	cpu_local_inc((l))
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#define __cpu_local_dec(l)	cpu_local_dec((l))
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#define __cpu_local_add(i, l)	cpu_local_add((i), (l))
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#define __cpu_local_sub(i, l)	cpu_local_sub((i), (l))
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#endif /* _ASM_X86_LOCAL_H */
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