linux/kernel/irq/migration.c

#include <linux/irq.h>
#include <linux/interrupt.h>

#include "internals.h"

void irq_move_masked_irq(struct irq_data *idata)
{
	struct irq_desc *desc = irq_data_to_desc(idata);
	struct irq_chip *chip = idata->chip;

	if (likely(!irqd_is_setaffinity_pending(&desc->irq_data)))
		return;

	/*
	 * Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
	 */
	if (!irqd_can_balance(&desc->irq_data)) {
		WARN_ON(1);
		return;
	}

	irqd_clr_move_pending(&desc->irq_data);

	if (unlikely(cpumask_empty(desc->pending_mask)))
		return;

	if (!chip->irq_set_affinity)
		return;

	assert_raw_spin_locked(&desc->lock);

	/*
	 * If there was a valid mask to work with, please
	 * do the disable, re-program, enable sequence.
	 * This is *not* particularly important for level triggered
	 * but in a edge trigger case, we might be setting rte
	 * when an active trigger is coming in. This could
	 * cause some ioapics to mal-function.
	 * Being paranoid i guess!
	 *
	 * For correct operation this depends on the caller
	 * masking the irqs.
	 */
	if (likely(cpumask_any_and(desc->pending_mask, cpu_online_mask)
		   < nr_cpu_ids)) {
		int ret = chip->irq_set_affinity(&desc->irq_data,
						 desc->pending_mask, false);
		switch (ret) {
		case IRQ_SET_MASK_OK:
			cpumask_copy(desc->irq_data.affinity, desc->pending_mask);
		case IRQ_SET_MASK_OK_NOCOPY:
			irq_set_thread_affinity(desc);
		}
	}

	cpumask_clear(desc->pending_mask);
}

void irq_move_irq(struct irq_data *idata)
{
	bool masked;

	if (likely(!irqd_is_setaffinity_pending(idata)))
		return;

	if (unlikely(irqd_irq_disabled(idata)))
		return;

	/*
	 * Be careful vs. already masked interrupts. If this is a
	 * threaded interrupt with ONESHOT set, we can end up with an
	 * interrupt storm.
	 */
	masked = irqd_irq_masked(idata);
	if (!masked)
		idata->chip->irq_mask(idata);
	irq_move_masked_irq(idata);
	if (!masked)
		idata->chip->irq_unmask(idata);
}