PCI: allow pci_alloc_child_bus() to handle a NULL bridge

Allow pci_alloc_child_bus() to allocate buses without bridge devices.
Some SR-IOV devices can occupy more than one bus number, but there is no
explicit bridges because that have internal routing mechanism.

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5372d3699e08..2ee00962734b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -398,12 +398,10 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
         if (!child)
                 return NULL;
 
-        child->self = bridge;
         child->parent = parent;
         child->ops = parent->ops;
         child->sysdata = parent->sysdata;
         child->bus_flags = parent->bus_flags;
-        child->bridge = get_device(&bridge->dev);
 
         /* initialize some portions of the bus device, but don't register it
          * now as the parent is not properly set up yet.  This device will get
@@ -420,6 +418,12 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
         child->primary = parent->secondary;
         child->subordinate = 0xff;
 
+        if (!bridge)
+                return child;
+
+        child->self = bridge;
+        child->bridge = get_device(&bridge->dev);
+
         /* Set up default resource pointers and names.. */
         for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
                 child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];