1 files changed, 7 insertions, 2 deletions

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 5a83dde8ca0c..54a4d5223238 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -143,7 +143,10 @@ static unsigned int irq_domain_legacy_revmap(struct irq_domain *domain,
  * irq_domain_add_simple() - Allocate and register a simple irq_domain.
  * @of_node: pointer to interrupt controller's device tree node.
  * @size: total number of irqs in mapping
- * @first_irq: first number of irq block assigned to the domain
+ * @first_irq: first number of irq block assigned to the domain,
+ *      pass zero to assign irqs on-the-fly. This will result in a
+ *      linear IRQ domain so it is important to use irq_create_mapping()
+ *      for each used IRQ, especially when SPARSE_IRQ is enabled.
  * @ops: map/unmap domain callbacks
  * @host_data: Controller private data pointer
  *
@@ -191,6 +194,7 @@ struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
         /* A linear domain is the default */
         return irq_domain_add_linear(of_node, size, ops, host_data);
 }
+EXPORT_SYMBOL_GPL(irq_domain_add_simple);
 
 /**
  * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain.
@@ -397,11 +401,12 @@ static void irq_domain_disassociate_many(struct irq_domain *domain,
         while (count--) {
                 int irq = irq_base + count;
                 struct irq_data *irq_data = irq_get_irq_data(irq);
-                irq_hw_number_t hwirq = irq_data->hwirq;
+                irq_hw_number_t hwirq;
 
                 if (WARN_ON(!irq_data || irq_data->domain != domain))
                         continue;
 
+                hwirq = irq_data->hwirq;
                 irq_set_status_flags(irq, IRQ_NOREQUEST);
 
                 /* remove chip and handler */