These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / kernel / irq / cpuhotplug.c

diff --git a/kernel/kernel/irq/cpuhotplug.c b/kernel/kernel/irq/cpuhotplug.c
new file mode 100644 (file)
index 0000000..011f8c4
--- /dev/null
+++ b/kernel/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_debug("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);
+}