driver core: add way to get to bus kset

This allows an easier way to get to the kset associated with a struct
bus_type (you have three to choose from...)  This will make it easier to
move these fields to be dynamic in a future patch.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/bus.c

@@ -935,6 +935,12 @@ int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(bus_unregister_notifier);
 
+struct kset *bus_get_kset(struct bus_type *bus)
+{
+	return &bus->subsys;
+}
+EXPORT_SYMBOL_GPL(bus_get_kset);
+
 int __init buses_init(void)
 {
 	bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);

drivers/pci/hotplug/pci_hotplug_core.c

@@ -699,9 +699,12 @@ int __must_check pci_hp_change_slot_info(struct hotplug_slot *slot,
 static int __init pci_hotplug_init (void)
 {
 	int result;
+	struct kset *pci_bus_kset;
+
+	pci_bus_kset = bus_get_kset(&pci_bus_type);
 
 	pci_hotplug_slots_kset = kset_create_and_add("slots", NULL,
-						     &pci_bus_type.subsys.kobj);
+						     &pci_bus_kset->kobj);
 	if (!pci_hotplug_slots_kset) {
 		result = -ENOMEM;
 		err("Register subsys error\n");

include/linux/device.h

@@ -117,6 +117,8 @@ extern int bus_unregister_notifier(struct bus_type *bus,
 #define BUS_NOTIFY_UNBIND_DRIVER	0x00000004 /* driver about to be
 						      unbound */
 
+extern struct kset *bus_get_kset(struct bus_type *bus);
+
 struct device_driver {
 	const char		* name;
 	struct bus_type		* bus;