iommu/amd: Split upstream bus device lookup

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 6edbd0e..3a00b5c 100644 (file)
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -274,6 +274,18 @@ static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
        *from = to;
 }
 
+static struct pci_bus *find_hosted_bus(struct pci_bus *bus)
+{
+       while (!bus->self) {
+               if (!pci_is_root_bus(bus))
+                       bus = bus->parent;
+               else
+                       return ERR_PTR(-ENODEV);
+       }
+
+       return bus;
+}
+
 #define REQ_ACS_FLAGS  (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
 
 static struct pci_dev *get_isolation_root(struct pci_dev *pdev)
@@ -300,14 +312,9 @@ static struct pci_dev *get_isolation_root(struct pci_dev *pdev)
         * Finding the next device may require skipping virtual buses.
         */
        while (!pci_is_root_bus(dma_pdev->bus)) {
-               struct pci_bus *bus = dma_pdev->bus;
-
-               while (!bus->self) {
-                       if (!pci_is_root_bus(bus))
-                               bus = bus->parent;
-                       else
-                               goto root_bus;
-               }
+               struct pci_bus *bus = find_hosted_bus(dma_pdev->bus);
+               if (IS_ERR(bus))
+                       break;
 
                if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))
                        break;
@@ -315,7 +322,6 @@ static struct pci_dev *get_isolation_root(struct pci_dev *pdev)
                swap_pci_ref(&dma_pdev, pci_dev_get(bus->self));
        }
 
-root_bus:
        return dma_pdev;
 }