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Commit 8b28499a authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Jens Axboe
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smp: Consolidate the various smp_call_function_single() declensions 



__smp_call_function_single() and smp_call_function_single() share some
code that can be factorized: execute inline when the target is local,
check if the target is online, lock the csd, call generic_exec_single().

Lets move the common parts to generic_exec_single().

Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 08eed44c

kernel/smp.c

+39 −41
Original line number Diff line number Diff line
@@ -117,13 +117,43 @@ static void csd_unlock(struct call_single_data *csd) 
	csd->flags &= ~CSD_FLAG_LOCK;

}



static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);



/*

 * Insert a previously allocated call_single_data element

 * for execution on the given CPU. data must already have

 * ->func, ->info, and ->flags set.

 */

static void generic_exec_single(int cpu, struct call_single_data *csd, int wait)

static int generic_exec_single(int cpu, struct call_single_data *csd,

			       smp_call_func_t func, void *info, int wait)

{

	struct call_single_data csd_stack = { .flags = 0 };

	unsigned long flags;





	if (cpu == smp_processor_id()) {

		local_irq_save(flags);

		func(info);

		local_irq_restore(flags);

		return 0;

	}





	if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu))

		return -ENXIO;





	if (!csd) {

		csd = &csd_stack;

		if (!wait)

			csd = &__get_cpu_var(csd_data);

	}



	csd_lock(csd);



	csd->func = func;

	csd->info = info;



	if (wait)

		csd->flags |= CSD_FLAG_WAIT;
@@ -143,6 +173,8 @@ static void generic_exec_single(int cpu, struct call_single_data *csd, int wait) 


	if (wait)

		csd_lock_wait(csd);



	return 0;

}



/*
@@ -168,8 +200,6 @@ void generic_smp_call_function_single_interrupt(void) 
	}

}



static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);



/*

 * smp_call_function_single - Run a function on a specific CPU

 * @func: The function to run. This must be fast and non-blocking.
@@ -181,12 +211,8 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); 
int smp_call_function_single(int cpu, smp_call_func_t func, void *info,

			     int wait)

{

	struct call_single_data d = {

		.flags = 0,

	};

	unsigned long flags;

	int this_cpu;

	int err = 0;

	int err;



	/*

	 * prevent preemption and reschedule on another processor,
@@ -203,26 +229,7 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info, 
	WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()

		     && !oops_in_progress);



	if (cpu == this_cpu) {

		local_irq_save(flags);

		func(info);

		local_irq_restore(flags);

	} else {

		if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {

			struct call_single_data *csd = &d;



			if (!wait)

				csd = &__get_cpu_var(csd_data);



			csd_lock(csd);



			csd->func = func;

			csd->info = info;

			generic_exec_single(cpu, csd, wait);

		} else {

			err = -ENXIO;	/* CPU not online */

		}

	}

	err = generic_exec_single(cpu, NULL, func, info, wait);



	put_cpu();
@@ -285,9 +292,8 @@ EXPORT_SYMBOL_GPL(smp_call_function_any); 
 */

int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait)

{

	unsigned int this_cpu;

	unsigned long flags;

	int err = 0;

	int this_cpu;



	this_cpu = get_cpu();

	/*
@@ -296,20 +302,12 @@ int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait) 
	 * send smp call function interrupt to this cpu and as such deadlocks

	 * can't happen.

	 */

	WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled()

	WARN_ON_ONCE(cpu_online(this_cpu) && wait && irqs_disabled()

		     && !oops_in_progress);



	if (cpu == this_cpu) {

		local_irq_save(flags);

		csd->func(csd->info);

		local_irq_restore(flags);

	} else if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {

		csd_lock(csd);

		generic_exec_single(cpu, csd, wait);

	} else {

		err = -ENXIO;	/* CPU not online */

	}

	err = generic_exec_single(cpu, csd, csd->func, csd->info, wait);

	put_cpu();



	return err;

}

EXPORT_SYMBOL_GPL(__smp_call_function_single);