diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1b89c3407251..ca0a1d5d2983 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4587,7 +4587,8 @@ static int __init platform_optin_force_iommu(void)
 static int __init probe_acpi_namespace_devices(void)
 {
 	struct dmar_drhd_unit *drhd;
-	struct intel_iommu *iommu;
+	/* To avoid a -Wunused-but-set-variable warning. */
+	struct intel_iommu *iommu __maybe_unused;
 	struct device *dev;
 	int i, ret = 0;