[PATCH] acpi bridge hotadd: Take the PCI lock when modifying pci bus or device lists

With root bridge and pci bridge hot-plug, new buses and devices can be added
or removed at run time.  Protect the pci bus and device lists with the pci
lock when doing so.
Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/probe.c

@@ -374,8 +374,11 @@ struct pci_bus * __devinit pci_add_new_bus(struct pci_bus *parent, struct pci_de
 	struct pci_bus *child;
 
 	child = pci_alloc_child_bus(parent, dev, busnr);
-	if (child)
+	if (child) {
+		spin_lock(&pci_bus_lock);
 		list_add_tail(&child->node, &parent->children);
+		spin_unlock(&pci_bus_lock);
+	}
 	return child;
 }
 
@@ -765,7 +768,9 @@ pci_scan_single_device(struct pci_bus *bus, int devfn)
 	 * and the bus list for fixup functions, etc.
 	 */
 	INIT_LIST_HEAD(&dev->global_list);
+	spin_lock(&pci_bus_lock);
 	list_add_tail(&dev->bus_list, &bus->devices);
+	spin_unlock(&pci_bus_lock);
 
 	return dev;
 }
@@ -886,7 +891,9 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, int bus,
 		pr_debug("PCI: Bus %04x:%02x already known\n", pci_domain_nr(b), bus);
 		goto err_out;
 	}
+	spin_lock(&pci_bus_lock);
 	list_add_tail(&b->node, &pci_root_buses);
+	spin_unlock(&pci_bus_lock);
 
 	memset(dev, 0, sizeof(*dev));
 	dev->parent = parent;
@@ -928,7 +935,9 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, int bus,
 class_dev_reg_err:
 	device_unregister(dev);
 dev_reg_err:
+	spin_lock(&pci_bus_lock);
 	list_del(&b->node);
+	spin_unlock(&pci_bus_lock);
 err_out:
 	kfree(dev);
 	kfree(b);