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Commit 29c6d1bb authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
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md/raid5: Convert to hotplug state machine 



Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Neil Brown <neilb@suse.com>
Cc: linux-raid@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160818125731.27256-10-bigeasy@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 84a3f4db

drivers/md/raid5.c

+29 −55
Original line number Diff line number Diff line
@@ -6330,22 +6330,20 @@ static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu 
	return 0;

}



static void raid5_free_percpu(struct r5conf *conf)

static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)

{

	unsigned long cpu;

	struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);



	free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));

	return 0;

}



static void raid5_free_percpu(struct r5conf *conf)

{

	if (!conf->percpu)

		return;



#ifdef CONFIG_HOTPLUG_CPU

	unregister_cpu_notifier(&conf->cpu_notify);

#endif



	get_online_cpus();

	for_each_possible_cpu(cpu)

		free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));

	put_online_cpus();



	cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);

	free_percpu(conf->percpu);

}
@@ -6364,64 +6362,28 @@ static void free_conf(struct r5conf *conf) 
	kfree(conf);

}



#ifdef CONFIG_HOTPLUG_CPU

static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,

			      void *hcpu)

static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)

{

	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);

	long cpu = (long)hcpu;

	struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);

	struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);



	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

	if (alloc_scratch_buffer(conf, percpu)) {

			pr_err("%s: failed memory allocation for cpu%ld\n",

		pr_err("%s: failed memory allocation for cpu%u\n",

		       __func__, cpu);

			return notifier_from_errno(-ENOMEM);

		}

		break;

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

		free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));

		break;

	default:

		break;

		return -ENOMEM;

	}

	return NOTIFY_OK;

	return 0;

}

#endif



static int raid5_alloc_percpu(struct r5conf *conf)

{

	unsigned long cpu;

	int err = 0;



	conf->percpu = alloc_percpu(struct raid5_percpu);

	if (!conf->percpu)

		return -ENOMEM;



#ifdef CONFIG_HOTPLUG_CPU

	conf->cpu_notify.notifier_call = raid456_cpu_notify;

	conf->cpu_notify.priority = 0;

	err = register_cpu_notifier(&conf->cpu_notify);

	if (err)

		return err;

#endif



	get_online_cpus();

	for_each_present_cpu(cpu) {

		err = alloc_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));

		if (err) {

			pr_err("%s: failed memory allocation for cpu%ld\n",

			       __func__, cpu);

			break;

		}

	}

	put_online_cpus();



	err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);

	if (!err) {

		conf->scribble_disks = max(conf->raid_disks,

			conf->previous_raid_disks);
@@ -7953,10 +7915,21 @@ static struct md_personality raid4_personality = 


static int __init raid5_init(void)

{

	int ret;



	raid5_wq = alloc_workqueue("raid5wq",

		WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);

	if (!raid5_wq)

		return -ENOMEM;



	ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,

				      "md/raid5:prepare",

				      raid456_cpu_up_prepare,

				      raid456_cpu_dead);

	if (ret) {

		destroy_workqueue(raid5_wq);

		return ret;

	}

	register_md_personality(&raid6_personality);

	register_md_personality(&raid5_personality);

	register_md_personality(&raid4_personality);
@@ -7968,6 +7941,7 @@ static void raid5_exit(void) 
	unregister_md_personality(&raid6_personality);

	unregister_md_personality(&raid5_personality);

	unregister_md_personality(&raid4_personality);

	cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);

	destroy_workqueue(raid5_wq);

}

drivers/md/raid5.h

+1 −3
Original line number Diff line number Diff line
@@ -512,9 +512,7 @@ struct r5conf { 
	} __percpu *percpu;

	int scribble_disks;

	int scribble_sectors;

#ifdef CONFIG_HOTPLUG_CPU

	struct notifier_block	cpu_notify;

#endif

	struct hlist_node node;



	/*

	 * Free stripes pool

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ enum cpuhp_state { 
	CPUHP_SMPCFD_PREPARE,

	CPUHP_RELAY_PREPARE,

	CPUHP_SLAB_PREPARE,

	CPUHP_MD_RAID5_PREPARE,

	CPUHP_RCUTREE_PREP,

	CPUHP_NOTIFY_PREPARE,

	CPUHP_TIMERS_DEAD,