Merge branch 'pci/iommu'

- Fix a Time-of-Check to Time-of-Use issue when testing driver_managed_dma
  in the IOMMU probe path (Robin Murphy)

* pci/iommu:
  PCI: Fix driver_managed_dma check

Author: bjorn-helgaas

drivers/pci/pci-driver.c

@@ -1628,7 +1628,7 @@ static int pci_bus_num_vf(struct device *dev)
  */
 static int pci_dma_configure(struct device *dev)
 {
-	struct pci_driver *driver = to_pci_driver(dev->driver);
+	const struct device_driver *drv = READ_ONCE(dev->driver);
 	struct device *bridge;
 	int ret = 0;
 
@@ -1645,8 +1645,8 @@ static int pci_dma_configure(struct device *dev)
 
 	pci_put_host_bridge_device(bridge);
 
-	/* @driver may not be valid when we're called from the IOMMU layer */
-	if (!ret && dev->driver && !driver->driver_managed_dma) {
+	/* @drv may not be valid when we're called from the IOMMU layer */
+	if (!ret && drv && !to_pci_driver(drv)->driver_managed_dma) {
 		ret = iommu_device_use_default_domain(dev);
 		if (ret)
 			arch_teardown_dma_ops(dev);