+/** pci_walk_bus - walk devices on/under bus, calling callback.
+ * @top bus whose devices should be walked
+ * @cb callback to be called for each device found
+ * @userdata arbitrary pointer to be passed to callback.
+ *
+ * Walk the given bus, including any bridged devices
+ * on buses under this bus. Call the provided callback
+ * on each device found.
+ */
+void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *),
+ void *userdata)
+{
+ struct pci_dev *dev;
+ struct pci_bus *bus;
+ struct list_head *next;
+
+ bus = top;
+ down_read(&pci_bus_sem);
+ next = top->devices.next;
+ for (;;) {
+ if (next == &bus->devices) {
+ /* end of this bus, go up or finish */
+ if (bus == top)
+ break;
+ next = bus->self->bus_list.next;
+ bus = bus->self->bus;
+ continue;
+ }
+ dev = list_entry(next, struct pci_dev, bus_list);
+ if (dev->subordinate) {
+ /* this is a pci-pci bridge, do its devices next */
+ next = dev->subordinate->devices.next;
+ bus = dev->subordinate;
+ } else
+ next = dev->bus_list.next;
+
+ /* Run device routines with the device locked */
+ down(&dev->dev.sem);
+ cb(dev, userdata);
+ up(&dev->dev.sem);
+ }
+ up_read(&pci_bus_sem);
+}
+EXPORT_SYMBOL_GPL(pci_walk_bus);
+