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/*
* Generic cpu hotunplug interrupt migration code copied from the
* arch/arm implementation
*
* Copyright (C) Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/interrupt.h>
#include <linux/ratelimit.h>
#include <linux/irq.h>
#include "internals.h"
/* For !GENERIC_IRQ_EFFECTIVE_AFF_MASK this looks at general affinity mask */
static inline bool irq_needs_fixup(struct irq_data *d)
{
const struct cpumask *m = irq_data_get_effective_affinity_mask(d);
return cpumask_test_cpu(smp_processor_id(), m);
}
static bool migrate_one_irq(struct irq_desc *desc)
{
struct irq_data *d = irq_desc_get_irq_data(desc);
struct irq_chip *chip = irq_data_get_irq_chip(d);
bool maskchip = !irq_can_move_pcntxt(d) && !irqd_irq_masked(d);
const struct cpumask *affinity;
bool brokeaff = false;
int err;
/*
* IRQ chip might be already torn down, but the irq descriptor is
* still in the radix tree. Also if the chip has no affinity setter,
* nothing can be done here.
*/
if (!chip || !chip->irq_set_affinity) {
pr_debug("IRQ %u: Unable to migrate away\n", d->irq);
return false;
}
/*
* No move required, if:
* - Interrupt is per cpu
* - Interrupt is not started
* - Affinity mask does not include this CPU.
*
* Note: Do not check desc->action as this might be a chained
* interrupt.
*/
if (irqd_is_per_cpu(d) || !irqd_is_started(d) || !irq_needs_fixup(d)) {
/*
* If an irq move is pending, abort it if the dying CPU is
* the sole target.
*/
irq_fixup_move_pending(desc, false);
return false;
}
/*
* Complete an eventually pending irq move cleanup. If this
* interrupt was moved in hard irq context, then the vectors need
* to be cleaned up. It can't wait until this interrupt actually
* happens and this CPU was involved.
*/
irq_force_complete_move(desc);
/*
* If there is a setaffinity pending, then try to reuse the pending
* mask, so the last change of the affinity does not get lost. If
* there is no move pending or the pending mask does not contain
* any online CPU, use the current affinity mask.
*/
if (irq_fixup_move_pending(desc, true))
affinity = irq_desc_get_pending_mask(desc);
else
affinity = irq_data_get_affinity_mask(d);
/* Mask the chip for interrupts which cannot move in process context */
if (maskchip && chip->irq_mask)
chip->irq_mask(d);
if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
affinity = cpu_online_mask;
brokeaff = true;
}
err = irq_do_set_affinity(d, affinity, true);
if (err) {
pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
d->irq, err);
brokeaff = false;
}
if (maskchip && chip->irq_unmask)
chip->irq_unmask(d);
return brokeaff;
}
/**
* irq_migrate_all_off_this_cpu - Migrate irqs away from offline cpu
*
* The current CPU has been marked offline. Migrate IRQs off this CPU.
* If the affinity settings do not allow other CPUs, force them onto any
* available CPU.
*
* Note: we must iterate over all IRQs, whether they have an attached
* action structure or not, as we need to get chained interrupts too.
*/
void irq_migrate_all_off_this_cpu(void)
{
struct irq_desc *desc;
unsigned int irq;
for_each_active_irq(irq) {
bool affinity_broken;
desc = irq_to_desc(irq);
raw_spin_lock(&desc->lock);
affinity_broken = migrate_one_irq(desc);
raw_spin_unlock(&desc->lock);
if (affinity_broken) {
pr_warn_ratelimited("IRQ %u: no longer affine to CPU%u\n",
irq, smp_processor_id());
}
}
}
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