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Commit 53ce3d95 authored by Andrew Morton's avatar Andrew Morton Committed by Ingo Molnar
Browse files

smp_call_function_single(): be slightly less stupid 



If you do

	smp_call_function_single(expression-with-side-effects, ...)

then expression-with-side-effects never gets evaluated on UP builds.

As always, implementing it in C is the correct thing to do.

While we're there, uninline it for size and possible header dependency
reasons.

And create a new kernel/up.c, as a place in which to put
uniprocessor-specific code and storage.  It should mirror kernel/smp.c.

Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent abede81c

include/linux/smp.h

+3 −10
Original line number Diff line number Diff line
@@ -24,6 +24,9 @@ struct call_single_data { 
/* total number of cpus in this system (may exceed NR_CPUS) */

extern unsigned int total_cpus;



int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,

				int wait);



#ifdef CONFIG_SMP



#include <linux/preempt.h>
@@ -79,8 +82,6 @@ smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info, 
	return 0;

}



int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,

				int wait);

void __smp_call_function_single(int cpuid, struct call_single_data *data);



/*
@@ -140,14 +141,6 @@ static inline int up_smp_call_function(void (*func)(void *), void *info) 
static inline void smp_send_reschedule(int cpu) { }

#define num_booting_cpus()			1

#define smp_prepare_boot_cpu()			do {} while (0)

#define smp_call_function_single(cpuid, func, info, wait) \

({ \

	WARN_ON(cpuid != 0);	\

	local_irq_disable();	\

	(func)(info);		\

	local_irq_enable();	\

	0;			\

})

#define smp_call_function_mask(mask, func, info, wait) \

			(up_smp_call_function(func, info))

#define smp_call_function_many(mask, func, info, wait) \

kernel/Makefile

+5 −1
Original line number Diff line number Diff line
@@ -40,7 +40,11 @@ obj-$(CONFIG_RT_MUTEXES) += rtmutex.o 
obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o

obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o

obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o

obj-$(CONFIG_USE_GENERIC_SMP_HELPERS) += smp.o

ifeq ($(CONFIG_USE_GENERIC_SMP_HELPERS),y)

obj-y += smp.o

else

obj-y += up.o

endif

obj-$(CONFIG_SMP) += spinlock.o

obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o

obj-$(CONFIG_PROVE_LOCKING) += spinlock.o

kernel/up.c

0 → 100644
+18 −0
Original line number Diff line number Diff line 
/*

 * Uniprocessor-only support functions.  The counterpart to kernel/smp.c

 */



#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/smp.h>



int smp_call_function_single(int cpu, void (*func) (void *info), void *info,

				int wait)

{

	WARN_ON(cpuid != 0);

	local_irq_disable();

	(func)(info);

	local_irq_enable();

	return 0;

}

EXPORT_SYMBOL(smp_call_function_single);