Instead of directly passing NULL to the various irq_domain functions,
start by looking up the domain with a domain_token.

As domain_token is permanently set to NULL, the lookup function will
return the same value (no domain found) and the default will be used,
preserving the current behaviour.

Signed-off-by: Marc Zyngier <redacted>
---
  drivers/acpi/gsi.c | 22 +++++++++-------------
  1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/acpi/gsi.c b/drivers/acpi/gsi.c
index 38208f2..a745880 100644
--- a/drivers/acpi/gsi.c
+++ b/drivers/acpi/gsi.c

@@ -14,6 +14,8 @@

  enum acpi_irq_model_id acpi_irq_model;

+static void *acpi_gsi_domain_token;
+
  static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
  {
  	switch (polarity) {

@@ -45,12 +47,9 @@ static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
   */
  int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
  {
-	/*
-	 * Only default domain is supported at present, always find
-	 * the mapping corresponding to default domain by passing NULL
-	 * as irq_domain parameter
-	 */
-	*irq = irq_find_mapping(NULL, gsi);
+	struct irq_domain *d = irq_find_matching_host(acpi_gsi_domain_token);