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>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5372d36..2ee0096 100644 (file)
--- 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];