Commit fa688207 authored by David Daney's avatar David Daney Committed by Linus Torvalds
Browse files

smp: quit unconditionally enabling irq in on_each_cpu_mask and on_each_cpu_cond 



As in commit f21afc25 ("smp.h: Use local_irq_{save,restore}() in
!SMP version of on_each_cpu()"), we don't want to enable irqs if they
are not already enabled.  There are currently no known problematical
callers of these functions, but since it is a known failure pattern, we
preemptively fix them.

Since they are not trivial functions, make them non-inline by moving
them to up.c.  This also makes it so we don't have to fix #include
dependancies for preempt_{disable,enable}.

Signed-off-by: default avatarDavid Daney <david.daney@cavium.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c14c338c

include/linux/smp.h

+16 −46
Original line number Diff line number Diff line
@@ -29,6 +29,22 @@ extern unsigned int total_cpus; 
int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,

			     int wait);



/*

 * Call a function on processors specified by mask, which might include

 * the local one.

 */

void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,

		void *info, bool wait);



/*

 * Call a function on each processor for which the supplied function

 * cond_func returns a positive value. This may include the local

 * processor.

 */

void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

		smp_call_func_t func, void *info, bool wait,

		gfp_t gfp_flags);



#ifdef CONFIG_SMP



#include <linux/preempt.h>
@@ -100,22 +116,6 @@ static inline void call_function_init(void) { } 
 */

int on_each_cpu(smp_call_func_t func, void *info, int wait);



/*

 * Call a function on processors specified by mask, which might include

 * the local one.

 */

void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,

		void *info, bool wait);



/*

 * Call a function on each processor for which the supplied function

 * cond_func returns a positive value. This may include the local

 * processor.

 */

void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

		smp_call_func_t func, void *info, bool wait,

		gfp_t gfp_flags);



/*

 * Mark the boot cpu "online" so that it can call console drivers in

 * printk() and can access its per-cpu storage.
@@ -151,36 +151,6 @@ static inline int on_each_cpu(smp_call_func_t func, void *info, int wait) 
	return 0;

}



/*

 * Note we still need to test the mask even for UP

 * because we actually can get an empty mask from

 * code that on SMP might call us without the local

 * CPU in the mask.

 */

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

	do {						\

		if (cpumask_test_cpu(0, (mask))) {	\

			local_irq_disable();		\

			(func)(info);			\

			local_irq_enable();		\

		}					\

	} while (0)

/*

 * Preemption is disabled here to make sure the cond_func is called under the

 * same condtions in UP and SMP.

 */

#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\

	do {							\

		void *__info = (info);				\

		preempt_disable();				\

		if ((cond_func)(0, __info)) {			\

			local_irq_disable();			\

			(func)(__info);				\

			local_irq_enable();			\

		}						\

		preempt_enable();				\

	} while (0)



static inline void smp_send_reschedule(int cpu) { }

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

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

kernel/up.c

+39 −0
Original line number Diff line number Diff line
@@ -19,3 +19,42 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, 
	return 0;

}

EXPORT_SYMBOL(smp_call_function_single);



/*

 * Note we still need to test the mask even for UP

 * because we actually can get an empty mask from

 * code that on SMP might call us without the local

 * CPU in the mask.

 */

void on_each_cpu_mask(const struct cpumask *mask,

		      smp_call_func_t func, void *info, bool wait)

{

	unsigned long flags;



	if (cpumask_test_cpu(0, mask)) {

		local_irq_save(flags);

		func(info);

		local_irq_restore(flags);

	}

}

EXPORT_SYMBOL(on_each_cpu_mask);



/*

 * Preemption is disabled here to make sure the cond_func is called under the

 * same condtions in UP and SMP.

 */

void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

		      smp_call_func_t func, void *info, bool wait,

		      gfp_t gfp_flags)

{

	unsigned long flags;



	preempt_disable();

	if (cond_func(0, info)) {

		local_irq_save(flags);

		func(info);

		local_irq_restore(flags);

	}

	preempt_enable();

}

EXPORT_SYMBOL(on_each_cpu_cond);

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