arm64: use cpu_online_mask when using forced irq_set_affinity

Commit 01f8fa4f01d8("genirq: Allow forcing cpu affinity of interrupts") enabled the forced irq_set_affinity which previously refused to route an interrupt to an offline cpu. Commit ffde1de64012("irqchip: Gic: Support forced affinity setting") implements this force logic and disables the cpu online check for GIC interrupt controller. When __cpu_disable calls migrate_irqs, it disables the current cpu in cpu_online_mask and uses forced irq_set_affinity to migrate the IRQs away from the cpu but passes affinity mask with the cpu being offlined also included in it. When calling irq_set_affinity with force == true in a cpu hotplug path, the caller must ensure that the cpu being offlined is not present in the affinity mask or it may be selected as the target CPU, leading to the interrupt not being migrated. This patch uses cpu_online_mask when using forced irq_set_affinity so that the IRQs are properly migrated away. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arm64: use cpu_online_mask when using forced irq_set_affinity
Commit 01f8fa4f01d8("genirq: Allow forcing cpu affinity of interrupts") enabled the forced irq_set_affinity which previously refused to route an interrupt to an offline cpu. Commit ffde1de64012("irqchip: Gic: Support forced affinity setting") implements this force logic and disables the cpu online check for GIC interrupt controller. When __cpu_disable calls migrate_irqs, it disables the current cpu in cpu_online_mask and uses forced irq_set_affinity to migrate the IRQs away from the cpu but passes affinity mask with the cpu being offlined also included in it. When calling irq_set_affinity with force == true in a cpu hotplug path, the caller must ensure that the cpu being offlined is not present in the affinity mask or it may be selected as the target CPU, leading to the interrupt not being migrated. This patch uses cpu_online_mask when using forced irq_set_affinity so that the IRQs are properly migrated away. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Sudeep Holla · Catalin Marinas · Eric Lee · Eric Lee · Eric Lee · Eric Lee
1 parent 89ca3b8819
Showing 1 changed file with 7 additions and 3 deletions Side-by-side Diff
arch/arm64/kernel/irq.c
@@ -97,11 +97,15 @@
 	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;
+	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids)
 		ret = true;
-	}
  
+	/*
+	 * when using forced irq_set_affinity we must ensure that the cpu
+	 * being offlined is not present in the affinity mask, it may be
+	 * selected as the target CPU otherwise
+	 */
+	affinity = cpu_online_mask;
 	c = irq_data_get_irq_chip(d);
 	if (!c->irq_set_affinity)
 		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
...	...	@@ -97,11 +97,15 @@
97	97	if (irqd_is_per_cpu(d) \|\| !cpumask_test_cpu(smp_processor_id(), affinity))
98	98	return false;
99	99
100		- if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
101		- affinity = cpu_online_mask;
	100	+ if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids)
102	101	ret = true;
103		- }
104	102
	103	+ /*
	104	+ * when using forced irq_set_affinity we must ensure that the cpu
	105	+ * being offlined is not present in the affinity mask, it may be
	106	+ * selected as the target CPU otherwise
	107	+ */
	108	+ affinity = cpu_online_mask;
105	109	c = irq_data_get_irq_chip(d);
106	110	if (!c->irq_set_affinity)
107	111	pr_debug("IRQ%u: unable to set affinity\n", d->irq);