This adds a list of all PCI host bridges we find and a way to look up
the host bridge from a pci_dev.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/probe.c |   39 ++++++++++++++++++++++++++++++++++-----
 include/linux/pci.h |    5 +++++
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index da0d655..2ffe8a3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -15,6 +15,8 @@

 #define CARDBUS_LATENCY_TIMER  176     /* secondary latency timer */
 #define CARDBUS_RESERVE_BUSNR  3

+static LIST_HEAD(pci_host_bridges);
+
 /* Ugh.  Need to stop exporting this to modules. */
 LIST_HEAD(pci_root_buses);
 EXPORT_SYMBOL(pci_root_buses);

@@ -42,6 +44,23 @@ int no_pci_devices(void)

 }
 EXPORT_SYMBOL(no_pci_devices);

+static struct pci_host_bridge *pci_host_bridge(struct pci_dev *dev)
+{
+       struct pci_bus *bus;
+       struct pci_host_bridge *bridge;
+
+       bus = dev->bus;
+       while (bus->parent)
+               bus = bus->parent;
+
+       list_for_each_entry(bridge, &pci_host_bridges, list) {
+               if (bridge->bus == bus)
+                       return bridge;
+       }
+
+       return NULL;
+}
+

 /*
 * PCI Bus Class
 */

@@ -1526,20 +1545,23 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,

               struct pci_ops *ops, void *sysdata, struct list_head *resources)
 {
       int error, i;
+       struct pci_host_bridge *bridge;
       struct pci_bus *b, *b2;
       struct device *dev;
       struct pci_bus_resource *bus_res, *n;
       struct resource *res;

+       bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
+       if (!bridge)
+               return NULL;
+
       b = pci_alloc_bus();
       if (!b)
-               return NULL;
+               goto err_bus;

       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-       if (!dev) {
-               kfree(b);
-               return NULL;
-       }
+       if (!dev)
+               goto err_dev;

       b->sysdata = sysdata;
       b->ops = ops;

@@ -1576,6 +1598,8 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,

       b->number = b->secondary = bus;

+       bridge->bus = b;
+
       /* Add initial resources to the bus */
       list_for_each_entry_safe(bus_res, n, resources, list)
               list_move_tail(&bus_res->list, &b->resources);

@@ -1591,6 +1615,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,

       }

       down_write(&pci_bus_sem);
+       list_add_tail(&bridge->list, &pci_host_bridges);
       list_add_tail(&b->node, &pci_root_buses);
       up_write(&pci_bus_sem);

@@ -1600,11 +1625,15 @@ class_dev_reg_err:

       device_unregister(dev);
 dev_reg_err:
       down_write(&pci_bus_sem);
+       list_del(&bridge->list);
       list_del(&b->node);
       up_write(&pci_bus_sem);
 err_out:
       kfree(dev);
+err_dev:
       kfree(b);
+err_bus:
+       kfree(bridge);
       return NULL;
 }

diff --git a/include/linux/pci.h b/include/linux/pci.h
index a16b1df..dfb2b64 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h

@@ -388,6 +388,11 @@ static inline void pci_add_saved_cap(struct pci_dev *pci_dev,

       hlist_add_head(&new_cap->next, &pci_dev->saved_cap_space);
 }

+struct pci_host_bridge {
+       struct list_head list;
+       struct pci_bus *bus;            /* root bus */
+};
+