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authorYang Yingliang <yangyingliang@huawei.com>2015-09-24 17:32:13 +0800
committerThomas Gleixner <tglx@linutronix.de>2015-10-01 14:51:15 +0200
commitf1e0bb0ad473a32d1b7e6d285ae9f7e47710bb5e (patch)
tree2059f76499d9ca8390194a55e1c4a06216e47ef9 /kernel/irq/cpuhotplug.c
parent9ffecb10283508260936b96022d4ee43a7798b4c (diff)
downloadlinux-stericsson-f1e0bb0ad473a32d1b7e6d285ae9f7e47710bb5e.tar.gz
genirq: Introduce generic irq migration for cpu hotunplug
ARM and ARM64 have almost identical code for migrating interrupts on cpu hotunplug. Provide a generic version which can be used by both. The new code addresses a shortcoming in the ARM[64] variants which fails to update the affinity change in some cases. The solution for this is to use the core function irq_do_set_affinity() instead of open coding it. [ tglx: Added copyright notice and license boilerplate. Rewrote subject and changelog. ] Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Acked-by: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Hanjun Guo <hanjun.guo@linaro.org> Cc: <linux-arm-kernel@lists.infradead.org> Link: http://lkml.kernel.org/r/1443087135-17044-2-git-send-email-yangyingliang@huawei.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq/cpuhotplug.c')
-rw-r--r--kernel/irq/cpuhotplug.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
new file mode 100644
index 000000000000..80f4f4e56fed
--- /dev/null
+++ b/kernel/irq/cpuhotplug.c
@@ -0,0 +1,82 @@
+/*
+ * 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"
+
+static bool migrate_one_irq(struct irq_desc *desc)
+{
+ struct irq_data *d = irq_desc_get_irq_data(desc);
+ const struct cpumask *affinity = d->common->affinity;
+ struct irq_chip *c;
+ bool ret = false;
+
+ /*
+ * If this is a per-CPU interrupt, or the affinity does not
+ * include this CPU, then we have nothing to do.
+ */
+ if (irqd_is_per_cpu(d) ||
+ !cpumask_test_cpu(smp_processor_id(), affinity))
+ return false;
+
+ if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
+ affinity = cpu_online_mask;
+ ret = true;
+ }
+
+ c = irq_data_get_irq_chip(d);
+ if (!c->irq_set_affinity) {
+ pr_warn_ratelimited("IRQ%u: unable to set affinity\n", d->irq);
+ } else {
+ int r = irq_do_set_affinity(d, affinity, false);
+ if (r)
+ pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
+ d->irq, r);
+ }
+
+ return ret;
+}
+
+/**
+ * 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)
+{
+ unsigned int irq;
+ struct irq_desc *desc;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ 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());
+ }
+
+ local_irq_restore(flags);
+}