[PATCH 4/15 v5] PCI: make pci_alloc_child_bus() be able to handleNULL bridge

[Yu Zhao]

Make pci_alloc_child_bus() be able to handle buses without bridge
devices. Some devices such as SR-IOV devices use more than one bus
number while there is no explicit bridge devices since they have
internal routing mechanism.

Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Cc: Grant Grundler <grundler@xxxxxxxxxxxxxxxx>
Cc: Alex Chiang <achiang@xxxxxx>
Cc: Matthew Wilcox <matthew@xxxxxx>
Cc: Roland Dreier <rdreier@xxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>

---
 drivers/pci/probe.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index db3e5a7..4b12b58 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -401,12 +401,10 @@ 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
@@ -423,6 +421,11 @@ 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_RES_NUM; i++) {
 		child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];
-- 
1.5.6.4

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