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Commit dfbbd86a authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
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s390/smp: Convert to hotplug state machine 



cpuhp_setup_state() invokes the startup callback on all online cpus with
the proper protection, so we can remove the cpu hotplug protection from the
init function and the creation of the per cpu files for online cpus in
smp_add_present_cpu(). smp_add_present_cpu() is called also called from
__smp_rescan_cpus(), but this callpath never adds an online cpu, it merily
adds newly present cpus, so the creation of the cpu files is not required.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161104144502.7kd4bxz2rxqvtack@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent ef65d45c

arch/s390/kernel/smp.c

+11 −26
Original line number Diff line number Diff line
@@ -1047,23 +1047,18 @@ static struct attribute_group cpu_online_attr_group = { 
	.attrs = cpu_online_attrs,

};



static int smp_cpu_notify(struct notifier_block *self, unsigned long action,

			  void *hcpu)

static int smp_cpu_online(unsigned int cpu)

{

	unsigned int cpu = (unsigned int)(long)hcpu;

	struct device *s = &per_cpu(cpu_device, cpu)->dev;

	int err = 0;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_ONLINE:

	case CPU_DOWN_FAILED:

		err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);

		break;

	case CPU_DOWN_PREPARE:

		sysfs_remove_group(&s->kobj, &cpu_online_attr_group);

		break;

	return sysfs_create_group(&s->kobj, &cpu_online_attr_group);

}

	return notifier_from_errno(err);

static int smp_cpu_pre_down(unsigned int cpu)

{

	struct device *s = &per_cpu(cpu_device, cpu)->dev;



	sysfs_remove_group(&s->kobj, &cpu_online_attr_group);

	return 0;

}



static int smp_add_present_cpu(int cpu)
@@ -1084,20 +1079,12 @@ static int smp_add_present_cpu(int cpu) 
	rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);

	if (rc)

		goto out_cpu;

	if (cpu_online(cpu)) {

		rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);

		if (rc)

			goto out_online;

	}

	rc = topology_cpu_init(c);

	if (rc)

		goto out_topology;

	return 0;



out_topology:

	if (cpu_online(cpu))

		sysfs_remove_group(&s->kobj, &cpu_online_attr_group);

out_online:

	sysfs_remove_group(&s->kobj, &cpu_common_attr_group);

out_cpu:

#ifdef CONFIG_HOTPLUG_CPU
@@ -1150,17 +1137,15 @@ static int __init s390_smp_init(void) 
	if (rc)

		return rc;

#endif

	cpu_notifier_register_begin();

	for_each_present_cpu(cpu) {

		rc = smp_add_present_cpu(cpu);

		if (rc)

			goto out;

	}



	__hotcpu_notifier(smp_cpu_notify, 0);



	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",

			       smp_cpu_online, smp_cpu_pre_down);

out:

	cpu_notifier_register_done();

	return rc;

}

subsys_initcall(s390_smp_init);