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Commit f73be6de authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

smp: have smp_call_function_single() detect invalid CPUs 



Have smp_call_function_single() return invalid CPU indicies and return
-ENXIO.  This function is already executed inside a
get_cpu()..put_cpu() which locks out CPU removal, so rather than
having the higher layers doing another layer of locking to guard
against unplugged CPUs do the test here.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 2a61812a

kernel/smp.c

+7 −3
Original line number Diff line number Diff line
@@ -210,8 +210,10 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, 
{

	struct call_single_data d;

	unsigned long flags;

	/* prevent preemption and reschedule on another processor */

	/* prevent preemption and reschedule on another processor,

	   as well as CPU removal */

	int me = get_cpu();

	int err = 0;



	/* Can deadlock when called with interrupts disabled */

	WARN_ON(irqs_disabled());
@@ -220,7 +222,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, 
		local_irq_save(flags);

		func(info);

		local_irq_restore(flags);

	} else {

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

		struct call_single_data *data = NULL;



		if (!wait) {
@@ -236,10 +238,12 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, 
		data->func = func;

		data->info = info;

		generic_exec_single(cpu, data);

	} else {

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

	}



	put_cpu();

	return 0;

	return err;

}

EXPORT_SYMBOL(smp_call_function_single);