1 files changed, 132 insertions, 25 deletions

diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index 011f8c4c63da..638eb9c83d9f 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -14,37 +14,104 @@
 
 #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);
-	const struct cpumask *affinity = d->common->affinity;
-	struct irq_chip *c;
-	bool ret = false;
+	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;
 
 	/*
-	 * If this is a per-CPU interrupt, or the affinity does not
-	 * include this CPU, then we have nothing to do.
+	 * 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 (irqd_is_per_cpu(d) ||
-	    !cpumask_test_cpu(smp_processor_id(), affinity))
+	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) {
+		/*
+		 * If the interrupt is managed, then shut it down and leave
+		 * the affinity untouched.
+		 */
+		if (irqd_affinity_is_managed(d)) {
+			irqd_set_managed_shutdown(d);
+			irq_shutdown(desc);
+			return false;
+		}
 		affinity = cpu_online_mask;
-		ret = true;
+		brokeaff = 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);
+	/*
+	 * Do not set the force argument of irq_do_set_affinity() as this
+	 * disables the masking of offline CPUs from the supplied affinity
+	 * mask and therefore might keep/reassign the irq to the outgoing
+	 * CPU.
+	 */
+	err = irq_do_set_affinity(d, affinity, false);
+	if (err) {
+		pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
+				    d->irq, err);
+		brokeaff = false;
 	}
 
-	return ret;
+	if (maskchip && chip->irq_unmask)
+		chip->irq_unmask(d);
+
+	return brokeaff;
 }
 
 /**
@@ -59,11 +126,8 @@ static bool migrate_one_irq(struct irq_desc *desc)
  */
 void irq_migrate_all_off_this_cpu(void)
 {
-	unsigned int irq;
 	struct irq_desc *desc;
-	unsigned long flags;
-
-	local_irq_save(flags);
+	unsigned int irq;
 
 	for_each_active_irq(irq) {
 		bool affinity_broken;
@@ -73,10 +137,53 @@ void irq_migrate_all_off_this_cpu(void)
 		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",
+		if (affinity_broken) {
+			pr_warn_ratelimited("IRQ %u: no longer affine to CPU%u\n",
 					    irq, smp_processor_id());
+		}
+	}
+}
+
+static void irq_restore_affinity_of_irq(struct irq_desc *desc, unsigned int cpu)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	const struct cpumask *affinity = irq_data_get_affinity_mask(data);
+
+	if (!irqd_affinity_is_managed(data) || !desc->action ||
+	    !irq_data_get_irq_chip(data) || !cpumask_test_cpu(cpu, affinity))
+		return;
+
+	if (irqd_is_managed_and_shutdown(data)) {
+		irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
+		return;
+	}
+
+	/*
+	 * If the interrupt can only be directed to a single target
+	 * CPU then it is already assigned to a CPU in the affinity
+	 * mask. No point in trying to move it around.
+	 */
+	if (!irqd_is_single_target(data))
+		irq_set_affinity_locked(data, affinity, false);
+}
+
+/**
+ * irq_affinity_online_cpu - Restore affinity for managed interrupts
+ * @cpu:	Upcoming CPU for which interrupts should be restored
+ */
+int irq_affinity_online_cpu(unsigned int cpu)
+{
+	struct irq_desc *desc;
+	unsigned int irq;
+
+	irq_lock_sparse();
+	for_each_active_irq(irq) {
+		desc = irq_to_desc(irq);
+		raw_spin_lock_irq(&desc->lock);
+		irq_restore_affinity_of_irq(desc, cpu);
+		raw_spin_unlock_irq(&desc->lock);
 	}
+	irq_unlock_sparse();
 
-	local_irq_restore(flags);
+	return 0;
 }