kernel/irq/numa_migrate.c

/*
 * NUMA irq-desc migration code
 *
 * Migrate IRQ data structures (irq_desc, chip_data, etc.) over to
 * the new "home node" of the IRQ.
 */

#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>

#include "internals.h"

static void init_copy_kstat_irqs(struct irq_desc *old_desc,
				 struct irq_desc *desc,
				 int node, int nr)
{
	init_kstat_irqs(desc, node, nr);

	if (desc->kstat_irqs != old_desc->kstat_irqs)
		memcpy(desc->kstat_irqs, old_desc->kstat_irqs,
			 nr * sizeof(*desc->kstat_irqs));
}

static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
{
	if (old_desc->kstat_irqs == desc->kstat_irqs)
		return;

	kfree(old_desc->kstat_irqs);
	old_desc->kstat_irqs = NULL;
}

static bool init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
		 struct irq_desc *desc, int node)
{
	memcpy(desc, old_desc, sizeof(struct irq_desc));
	if (!alloc_desc_masks(desc, node, false)) {
		printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
				"for migration.\n", irq);
		return false;
	}
	raw_spin_lock_init(&desc->lock);
	desc->node = node;
	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
	init_copy_kstat_irqs(old_desc, desc, node, nr_cpu_ids);
	init_copy_desc_masks(old_desc, desc);
	arch_init_copy_chip_data(old_desc, desc, node);
	return true;
}

static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
{
	free_kstat_irqs(old_desc, desc);
	free_desc_masks(old_desc, desc);
	arch_free_chip_data(old_desc, desc);
}

static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
						int node)
{
	struct irq_desc *desc;
	unsigned int irq;
	unsigned long flags;

	irq = old_desc->irq;

	raw_spin_lock_irqsave(&sparse_irq_lock, flags);

	/* We have to check it to avoid races with another CPU */
	desc = irq_to_desc(irq);

	if (desc && old_desc != desc)
		goto out_unlock;

	desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
	if (!desc) {
		printk(KERN_ERR "irq %d: can not get new irq_desc "
				"for migration.\n", irq);
		/* still use old one */
		desc = old_desc;
		goto out_unlock;
	}
	if (!init_copy_one_irq_desc(irq, old_desc, desc, node)) {
		/* still use old one */
		kfree(desc);
		desc = old_desc;
		goto out_unlock;
	}

	replace_irq_desc(irq, desc);
	raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);

	/* free the old one */
	free_one_irq_desc(old_desc, desc);
	kfree(old_desc);

	return desc;

out_unlock:
	raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);

	return desc;
}

struct irq_desc *move_irq_desc(struct irq_desc *desc, int node)
{
	/* those static or target node is -1, do not move them */
	if (desc->irq < NR_IRQS_LEGACY || node == -1)
		return desc;

	if (desc->node != node)
		desc = __real_move_irq_desc(desc, node);

	return desc;
}