[PATCH 4/8] PCI: make pci_host_bridge more robust

Yinghai Lu
2012-02-26T23:33:52Z

1. change pci_host_bridge to find_pci_root_bridge.
2. separate find_pci_root_bus().
3. on any possible path return NULL.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
drivers/pci/host-bridge.c | 35 ++++++++++++++++++++++++++++-------
1 file changed, 28 insertions(+), 7 deletions(-)

Index: linux-2.6/drivers/pci/host-bridge.c
===================================================================
--- linux-2.6.orig/drivers/pci/host-bridge.c
+++ linux-2.6/drivers/pci/host-bridge.c
@@ -16,19 +16,31 @@ void add_to_pci_host_bridges(struct pci_
list_add_tail(&bridge->list, &pci_host_bridges);
}

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

return NULL;
}
@@ -42,10 +54,13 @@ void __weak pcibios_resource_to_bus(stru
struct pci_bus_region *region,
struct resource *res)
{
- struct pci_host_bridge *bridge = pci_host_bridge(dev);
+ struct pci_host_bridge *bridge = find_pci_host_bridge(dev);
struct pci_host_bridge_window *window;
resource_size_t offset = 0;

+ if (!bridge)
+ goto no_bridge;
+
list_for_each_entry(window, &bridge->windows, list) {
if (resource_type(res) != resource_type(window->res))
continue;
@@ -56,6 +71,7 @@ void __weak pcibios_resource_to_bus(stru
}
}

+no_bridge:
region->start = res->start - offset;
region->end = res->end - offset;
}
@@ -70,12 +86,16 @@ static bool region_contains(struct pci_b
void __weak pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
struct pci_bus_region *region)
{
- struct pci_host_bridge *bridge = pci_host_bridge(dev);
+ struct pci_host_bridge *bridge = find_pci_host_bridge(dev);
struct pci_host_bridge_window *window;
- struct pci_bus_region bus_region;
resource_size_t offset = 0;

+ if (!bridge)
+ goto no_bridge;
+
list_for_each_entry(window, &bridge->windows, list) {
+ struct pci_bus_region bus_region;
+
if (resource_type(res) != resource_type(window->res))
continue;

@@ -88,6 +108,7 @@ void __weak pcibios_bus_to_resource(stru
}
}

+no_bridge:
res->start = region->start + offset;
res->end = region->end + offset;
}