diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 83c8e617a2c58..35291b02aab1a 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -90,6 +90,7 @@ static const char * const iommu_group_resv_type_string[] = {
 #define IOMMU_CMD_LINE_DMA_API		BIT(0)
 #define IOMMU_CMD_LINE_STRICT		BIT(1)
 
+static int bus_iommu_probe(const struct bus_type *bus);
 static int iommu_bus_notifier(struct notifier_block *nb,
 			      unsigned long action, void *data);
 static void iommu_release_device(struct device *dev);
@@ -1795,7 +1796,7 @@ static void iommu_group_do_probe_finalize(struct device *dev)
 		ops->probe_finalize(dev);
 }
 
-int bus_iommu_probe(const struct bus_type *bus)
+static int bus_iommu_probe(const struct bus_type *bus)
 {
 	struct iommu_group *group, *next;
 	LIST_HEAD(group_list);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index bd722f4736352..84a6ed5e803a4 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -784,7 +784,6 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
 	};
 }
 
-extern int bus_iommu_probe(const struct bus_type *bus);
 extern bool iommu_present(const struct bus_type *bus);
 extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap);
 extern bool iommu_group_has_isolated_msi(struct iommu_group *group);