Re: [Ltt-dev] [PATCH 5/10] local_t : MIPS

[Mathieu Desnoyers]

Sorry, I meant MIPS.

* Mathieu Desnoyers (mathieu.desnoyers@xxxxxxxxxx) wrote:
> ia64 architecture local_t extension.
> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
> 
> --- a/include/asm-mips/system.h
> +++ b/include/asm-mips/system.h
> @@ -253,6 +253,58 @@ static inline unsigned long __cmpxchg_u3
>  	return retval;
>  }
>  
> +static inline unsigned long __cmpxchg_u32_local(volatile int * m,
> +	unsigned long old, unsigned long new)
> +{
> +	__u32 retval;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		__asm__ __volatile__(
> +		"	.set	push					\n"
> +		"	.set	noat					\n"
> +		"	.set	mips3					\n"
> +		"1:	ll	%0, %2			# __cmpxchg_u32	\n"
> +		"	bne	%0, %z3, 2f				\n"
> +		"	.set	mips0					\n"
> +		"	move	$1, %z4					\n"
> +		"	.set	mips3					\n"
> +		"	sc	$1, %1					\n"
> +		"	beqzl	$1, 1b					\n"
> +		"2:							\n"
> +		"	.set	pop					\n"
> +		: "=&r" (retval), "=R" (*m)
> +		: "R" (*m), "Jr" (old), "Jr" (new)
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		__asm__ __volatile__(
> +		"	.set	push					\n"
> +		"	.set	noat					\n"
> +		"	.set	mips3					\n"
> +		"1:	ll	%0, %2			# __cmpxchg_u32	\n"
> +		"	bne	%0, %z3, 2f				\n"
> +		"	.set	mips0					\n"
> +		"	move	$1, %z4					\n"
> +		"	.set	mips3					\n"
> +		"	sc	$1, %1					\n"
> +		"	beqz	$1, 1b					\n"
> +		"2:							\n"
> +		"	.set	pop					\n"
> +		: "=&r" (retval), "=R" (*m)
> +		: "R" (*m), "Jr" (old), "Jr" (new)
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		retval = *m;
> +		if (retval == old)
> +			*m = new;
> +		local_irq_restore(flags);	/* implies memory barrier  */
> +	}
> +
> +	return retval;
> +}
> +
>  #ifdef CONFIG_64BIT
>  static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old,
>  	unsigned long new)
> @@ -303,10 +355,62 @@ static inline unsigned long __cmpxchg_u6
>  
>  	return retval;
>  }
> +
> +static inline unsigned long __cmpxchg_u64_local(volatile int * m,
> +	unsigned long old, unsigned long new)
> +{
> +	__u64 retval;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		__asm__ __volatile__(
> +		"	.set	push					\n"
> +		"	.set	noat					\n"
> +		"	.set	mips3					\n"
> +		"1:	lld	%0, %2			# __cmpxchg_u64	\n"
> +		"	bne	%0, %z3, 2f				\n"
> +		"	move	$1, %z4					\n"
> +		"	scd	$1, %1					\n"
> +		"	beqzl	$1, 1b					\n"
> +		"2:							\n"
> +		"	.set	pop					\n"
> +		: "=&r" (retval), "=R" (*m)
> +		: "R" (*m), "Jr" (old), "Jr" (new)
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		__asm__ __volatile__(
> +		"	.set	push					\n"
> +		"	.set	noat					\n"
> +		"	.set	mips3					\n"
> +		"1:	lld	%0, %2			# __cmpxchg_u64	\n"
> +		"	bne	%0, %z3, 2f				\n"
> +		"	move	$1, %z4					\n"
> +		"	scd	$1, %1					\n"
> +		"	beqz	$1, 1b					\n"
> +		"2:							\n"
> +		"	.set	pop					\n"
> +		: "=&r" (retval), "=R" (*m)
> +		: "R" (*m), "Jr" (old), "Jr" (new)
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		retval = *m;
> +		if (retval == old)
> +			*m = new;
> +		local_irq_restore(flags);	/* implies memory barrier  */
> +	}
> +
> +	return retval;
> +}
> +
>  #else
>  extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
>  	volatile int * m, unsigned long old, unsigned long new);
>  #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
> +extern unsigned long __cmpxchg_u64_local_unsupported_on_32bit_kernels(
> +	volatile int * m, unsigned long old, unsigned long new);
> +#define __cmpxchg_u64_local __cmpxchg_u64_local_unsupported_on_32bit_kernels
>  #endif
>  
>  /* This function doesn't exist, so you'll get a linker error
> @@ -326,7 +430,26 @@ static inline unsigned long __cmpxchg(vo
>  	return old;
>  }
>  
> -#define cmpxchg(ptr,old,new) ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
> +static inline unsigned long __cmpxchg_local(volatile void * ptr,
> +	unsigned long old, unsigned long new, int size)
> +{
> +	switch (size) {
> +	case 4:
> +		return __cmpxchg_u32_local(ptr, old, new);
> +	case 8:
> +		return __cmpxchg_u64_local(ptr, old, new);
> +	}
> +	__cmpxchg_called_with_bad_pointer();
> +	return old;
> +}
> +
> +#define cmpxchg(ptr,old,new) \
> +	((__typeof__(*(ptr)))__cmpxchg((ptr), \
> +		(unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
> +
> +#define cmpxchg_local(ptr,old,new) \
> +	((__typeof__(*(ptr)))__cmpxchg_local((ptr), \
> +		(unsigned long)(old), (unsigned long)(new),sizeof(*(ptr))))
>  
>  extern void set_handler (unsigned long offset, void *addr, unsigned long len);
>  extern void set_uncached_handler (unsigned long offset, void *addr, unsigned long len);
> --- a/include/asm-mips/local.h
> +++ b/include/asm-mips/local.h
> @@ -1,60 +1,527 @@
> -#ifndef _ASM_LOCAL_H
> -#define _ASM_LOCAL_H
> +#ifndef _ARCH_POWERPC_LOCAL_H
> +#define _ARCH_POWERPC_LOCAL_H
>  
>  #include <linux/percpu.h>
>  #include <asm/atomic.h>
>  
> -#ifdef CONFIG_32BIT
> +typedef struct
> +{
> +	local_long_t a;
> +} local_t;
>  
> -typedef atomic_t local_t;
> +#define LOCAL_INIT(i)	{ local_LONG_INIT(i) }
>  
> -#define LOCAL_INIT(i)	ATOMIC_INIT(i)
> -#define local_read(v)	atomic_read(v)
> -#define local_set(v,i)	atomic_set(v,i)
> +#define local_read(l)	local_long_read(&(l)->a)
> +#define local_set(l,i)	local_long_set(&(l)->a, (i))
>  
> -#define local_inc(v)	atomic_inc(v)
> -#define local_dec(v)	atomic_dec(v)
> -#define local_add(i, v)	atomic_add(i, v)
> -#define local_sub(i, v)	atomic_sub(i, v)
> +#define local_add(i,l)	local_long_add((i),(&(l)->a))
> +#define local_sub(i,l)	local_long_sub((i),(&(l)->a))
> +#define local_inc(l)	local_long_inc(&(l)->a)
> +#define local_dec(l)	local_long_dec(&(l)->a)
>  
> -#endif
>  
> -#ifdef CONFIG_64BIT
> +#ifndef CONFIG_64BITS
>  
> -typedef atomic64_t local_t;
> +/*
> + * Same as above, but return the result value
> + */
> +static __inline__ int local_add_return(int i, local_t * l)
> +{
> +	unsigned long result;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	ll	%1, %2		# local_add_return	\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	sc	%0, %2					\n"
> +		"	beqzl	%0, 1b					\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	ll	%1, %2		# local_add_return	\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	sc	%0, %2					\n"
> +		"	beqz	%0, 1b					\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		result = &(l->a.counter);
> +		result += i;
> +		&(l->a.counter) = result;
> +		local_irq_restore(flags);
> +	}
> +
> +	return result;
> +}
> +
> +static __inline__ int local_sub_return(int i, local_t * l)
> +{
> +	unsigned long result;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	ll	%1, %2		# local_sub_return	\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	sc	%0, %2					\n"
> +		"	beqzl	%0, 1b					\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	ll	%1, %2		# local_sub_return	\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	sc	%0, %2					\n"
> +		"	beqz	%0, 1b					\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		result = &(l->a.counter);
> +		result -= i;
> +		&(l->a.counter) = result;
> +		local_irq_restore(flags);
> +	}
> +
> +	return result;
> +}
> +
> +/*
> + * local_sub_if_positive - conditionally subtract integer from atomic variable
> + * @i: integer value to subtract
> + * @l: pointer of type local_t
> + *
> + * Atomically test @l and subtract @i if @l is greater or equal than @i.
> + * The function returns the old value of @l minus @i.
> + */
> +static __inline__ int local_sub_if_positive(int i, local_t * l)
> +{
> +	unsigned long result;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	ll	%1, %2		# local_sub_if_positive\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	bltz	%0, 1f					\n"
> +		"	sc	%0, %2					\n"
> +		"	.set	noreorder				\n"
> +		"	beqzl	%0, 1b					\n"
> +		"	 subu	%0, %1, %3				\n"
> +		"	.set	reorder					\n"
> +		"1:							\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	ll	%1, %2		# local_sub_if_positive\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	bltz	%0, 1f					\n"
> +		"	sc	%0, %2					\n"
> +		"	.set	noreorder				\n"
> +		"	beqz	%0, 1b					\n"
> +		"	 subu	%0, %1, %3				\n"
> +		"	.set	reorder					\n"
> +		"1:							\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		result = &(l->a.counter);
> +		result -= i;
> +		if (result >= 0)
> +			&(l->a.counter) = result;
> +		local_irq_restore(flags);
> +	}
> +
> +	return result;
> +}
> +
> +#define local_cmpxchg(l, o, n) \
> +	((long)cmpxchg(&((l)->a.counter), (o), (n)))
> +#define local_xchg(l, new) (xchg(&((l)->a.counter), new))
> +
> +/**
> + * local_add_unless - add unless the number is a given value
> + * @l: pointer of type local_t
> + * @a: the amount to add to l...
> + * @u: ...unless l is equal to u.
> + *
> + * Atomically adds @a to @l, so long as it was not @u.
> + * Returns non-zero if @l was not @u, and zero otherwise.
> + */
> +#define local_add_unless(l, a, u)				\
> +({								\
> +	long c, old;						\
> +	c = local_read(l);					\
> +	while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \
> +		c = old;					\
> +	c != (u);						\
> +})
> +#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
> +
> +#define local_dec_return(l) local_sub_return(1,(l))
> +#define local_inc_return(l) local_add_return(1,(l))
> +
> +/*
> + * local_sub_and_test - subtract value from variable and test result
> + * @i: integer value to subtract
> + * @l: pointer of type local_t
> + *
> + * Atomically subtracts @i from @l and returns
> + * true if the result is zero, or false for all
> + * other cases.
> + */
> +#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)
> +
> +/*
> + * local_inc_and_test - increment and test
> + * @l: pointer of type local_t
> + *
> + * Atomically increments @l by 1
> + * and returns true if the result is zero, or false for all
> + * other cases.
> + */
> +#define local_inc_and_test(l) (local_inc_return(l) == 0)
> +
> +/*
> + * local_dec_and_test - decrement by 1 and test
> + * @l: pointer of type local_t
> + *
> + * Atomically decrements @l by 1 and
> + * returns true if the result is 0, or false for all other
> + * cases.
> + */
> +#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
> +
> +/*
> + * local_dec_if_positive - decrement by 1 if old value positive
> + * @l: pointer of type local_t
> + */
> +#define local_dec_if_positive(l)	local_sub_if_positive(1, l)
> +
> +/*
> + * local_add_negative - add and test if negative
> + * @l: pointer of type local_t
> + * @i: integer value to add
> + *
> + * Atomically adds @i to @l and returns true
> + * if the result is negative, or false when
> + * result is greater than or equal to zero.
> + */
> +#define local_add_negative(i,l) (local_add_return(i, (l)) < 0)
> +
> +#else /* CONFIG_64BITS */
>  
> -#define LOCAL_INIT(i)	ATOMIC64_INIT(i)
> -#define local_read(v)	atomic64_read(v)
> -#define local_set(v,i)	atomic64_set(v,i)
> +/*
> + * Same as above, but return the result value
> + */
> +static __inline__ long local_add_return(long i, local_t * l)
> +{
> +	unsigned long result;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	lld	%1, %2		# local_add_return	\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	scd	%0, %2					\n"
> +		"	beqzl	%0, 1b					\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	lld	%1, %2		# local_add_return	\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	scd	%0, %2					\n"
> +		"	beqz	%0, 1b					\n"
> +		"	addu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		result = &(l->a.counter);
> +		result += i;
> +		&(l->a.counter) = result;
> +		local_irq_restore(flags);
> +	}
>  
> -#define local_inc(v)	atomic64_inc(v)
> -#define local_dec(v)	atomic64_dec(v)
> -#define local_add(i, v)	atomic64_add(i, v)
> -#define local_sub(i, v)	atomic64_sub(i, v)
> +	return result;
> +}
>  
> -#endif
> +static __inline__ long local_sub_return(long i, local_t * l)
> +{
> +	unsigned long result;
>  
> -#define __local_inc(v)		((v)->counter++)
> -#define __local_dec(v)		((v)->counter--)
> -#define __local_add(i,v)	((v)->counter+=(i))
> -#define __local_sub(i,v)	((v)->counter-=(i))
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	lld	%1, %2		# local_sub_return	\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	scd	%0, %2					\n"
> +		"	beqzl	%0, 1b					\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	lld	%1, %2		# local_sub_return	\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	scd	%0, %2					\n"
> +		"	beqz	%0, 1b					\n"
> +		"	subu	%0, %1, %3				\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		result = &(l->a.counter);
> +		result -= i;
> +		&(l->a.counter) = result;
> +		local_irq_restore(flags);
> +	}
> +
> +	return result;
> +}
>  
>  /*
> - * Use these for per-cpu local_t variables: on some archs they are
> + * local_sub_if_positive - conditionally subtract integer from atomic variable
> + * @i: integer value to subtract
> + * @l: pointer of type local_t
> + *
> + * Atomically test @l and subtract @i if @l is greater or equal than @i.
> + * The function returns the old value of @l minus @i.
> + */
> +static __inline__ long local_sub_if_positive(long i, local_t * l)
> +{
> +	unsigned long result;
> +
> +	if (cpu_has_llsc && R10000_LLSC_WAR) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	lld	%1, %2		# local_sub_if_positive\n"
> +		"	dsubu	%0, %1, %3				\n"
> +		"	bltz	%0, 1f					\n"
> +		"	scd	%0, %2					\n"
> +		"	.set	noreorder				\n"
> +		"	beqzl	%0, 1b					\n"
> +		"	 dsubu	%0, %1, %3				\n"
> +		"	.set	reorder					\n"
> +		"1:							\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else if (cpu_has_llsc) {
> +		unsigned long temp;
> +
> +		__asm__ __volatile__(
> +		"	.set	mips3					\n"
> +		"1:	lld	%1, %2		# local_sub_if_positive\n"
> +		"	dsubu	%0, %1, %3				\n"
> +		"	bltz	%0, 1f					\n"
> +		"	scd	%0, %2					\n"
> +		"	.set	noreorder				\n"
> +		"	beqz	%0, 1b					\n"
> +		"	 dsubu	%0, %1, %3				\n"
> +		"	.set	reorder					\n"
> +		"1:							\n"
> +		"	.set	mips0					\n"
> +		: "=&r" (result), "=&r" (temp), "=m" (&(l->a.counter))
> +		: "Ir" (i), "m" (&(l->a.counter))
> +		: "memory");
> +	} else {
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
> +		result = &(l->a.counter);
> +		result -= i;
> +		if (result >= 0)
> +			&(l->a.counter) = result;
> +		local_irq_restore(flags);
> +	}
> +
> +	return result;
> +}
> +
> +
> +#define local_cmpxchg(l, o, n) \
> +	((long)cmpxchg(&((l)->a.counter), (o), (n)))
> +#define local_xchg(l, new) (xchg(&((l)->a.counter), new))
> +
> +/**
> + * local_add_unless - add unless the number is a given value
> + * @l: pointer of type local_t
> + * @a: the amount to add to l...
> + * @u: ...unless l is equal to u.
> + *
> + * Atomically adds @a to @l, so long as it was not @u.
> + * Returns non-zero if @l was not @u, and zero otherwise.
> + */
> +#define local_add_unless(l, a, u)				\
> +({								\
> +	long c, old;						\
> +	c = local_read(l);					\
> +	while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \
> +		c = old;					\
> +	c != (u);						\
> +})
> +#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
> +
> +#define local_dec_return(l) local_sub_return(1,(l))
> +#define local_inc_return(l) local_add_return(1,(l))
> +
> +/*
> + * local_sub_and_test - subtract value from variable and test result
> + * @i: integer value to subtract
> + * @l: pointer of type local_t
> + *
> + * Atomically subtracts @i from @l and returns
> + * true if the result is zero, or false for all
> + * other cases.
> + */
> +#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)
> +
> +/*
> + * local_inc_and_test - increment and test
> + * @l: pointer of type local_t
> + *
> + * Atomically increments @l by 1
> + * and returns true if the result is zero, or false for all
> + * other cases.
> + */
> +#define local_inc_and_test(l) (local_inc_return(l) == 0)
> +
> +/*
> + * local_dec_and_test - decrement by 1 and test
> + * @l: pointer of type local_t
> + *
> + * Atomically decrements @l by 1 and
> + * returns true if the result is 0, or false for all other
> + * cases.
> + */
> +#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
> +
> +/*
> + * local_dec_if_positive - decrement by 1 if old value positive
> + * @l: pointer of type local_t
> + */
> +#define local_dec_if_positive(l)	local_sub_if_positive(1, l)
> +
> +/*
> + * local_add_negative - add and test if negative
> + * @l: pointer of type local_t
> + * @i: integer value to add
> + *
> + * Atomically adds @i to @l and returns true
> + * if the result is negative, or false when
> + * result is greater than or equal to zero.
> + */
> +#define local_add_negative(i,l) (local_add_return(i, (l)) < 0)
> +
> +#endif /* !CONFIG_64BITS */
> +
> +
> +/* Use these for per-cpu local_t variables: on some archs they are
>   * much more efficient than these naive implementations.  Note they take
>   * a variable, not an address.
> + *
> + * This could be done better if we moved the per cpu data directly
> + * after GS.
>   */
> -#define cpu_local_read(v)	local_read(&__get_cpu_var(v))
> -#define cpu_local_set(v, i)	local_set(&__get_cpu_var(v), (i))
>  
> -#define cpu_local_inc(v)	local_inc(&__get_cpu_var(v))
> -#define cpu_local_dec(v)	local_dec(&__get_cpu_var(v))
> -#define cpu_local_add(i, v)	local_add((i), &__get_cpu_var(v))
> -#define cpu_local_sub(i, v)	local_sub((i), &__get_cpu_var(v))
> +#define __local_inc(l)		((l)->a.counter++)
> +#define __local_dec(l)		((l)->a.counter++)
> +#define __local_add(i,l)	((l)->a.counter+=(i))
> +#define __local_sub(i,l)	((l)->a.counter-=(i))
> +
> +/* Need to disable preemption for the cpu local counters otherwise we could
> +   still access a variable of a previous CPU in a non atomic way. */
> +#define cpu_local_wrap_v(l)	 	\
> +	({ local_t res__;		\
> +	   preempt_disable(); 		\
> +	   res__ = (l);			\
> +	   preempt_enable();		\
> +	   res__; })
> +#define cpu_local_wrap(l)		\
> +	({ preempt_disable();		\
> +	   l;				\
> +	   preempt_enable(); })		\
> +
> +#define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
> +#define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
> +#define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))
> +#define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))
> +#define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
> +#define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
>  
> -#define __cpu_local_inc(v)	__local_inc(&__get_cpu_var(v))
> -#define __cpu_local_dec(v)	__local_dec(&__get_cpu_var(v))
> -#define __cpu_local_add(i, v)	__local_add((i), &__get_cpu_var(v))
> -#define __cpu_local_sub(i, v)	__local_sub((i), &__get_cpu_var(v))
> +#define __cpu_local_inc(l)	cpu_local_inc(l)
> +#define __cpu_local_dec(l)	cpu_local_dec(l)
> +#define __cpu_local_add(i, l)	cpu_local_add((i), (l))
> +#define __cpu_local_sub(i, l)	cpu_local_sub((i), (l))
>  
> -#endif /* _ASM_LOCAL_H */
> +#endif /* _ARCH_POWERPC_LOCAL_H */
> 

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