[RFC PATCH v1 05/22] PCI: introduce pci_bus_{get|put}() to manage PCI bus reference count

[Jiang Liu <liuj97@gmail.com>]

Sometimes PCI hotplug drivers need to hold a reference count on a PCI bus,
so introduce pci_bus_{get|put}() to manage PCI bus reference count.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/pci/bus.c   |   15 +++++++++++++++
 include/linux/pci.h |    2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index e2a0c52..0e18270 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -325,6 +325,21 @@ void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
 }
 EXPORT_SYMBOL_GPL(pci_walk_bus);
 
+struct pci_bus *pci_bus_get(struct pci_bus *bus)
+{
+	if (bus)
+		get_device(&bus->dev);
+	return bus;
+}
+EXPORT_SYMBOL(pci_bus_get);
+
+void pci_bus_put(struct pci_bus *bus)
+{
+	if (bus)
+		put_device(&bus->dev);
+}
+EXPORT_SYMBOL(pci_bus_put);
+
 EXPORT_SYMBOL(pci_bus_alloc_resource);
 EXPORT_SYMBOL_GPL(pci_bus_add_device);
 EXPORT_SYMBOL(pci_bus_add_devices);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 95479cd..21fa79e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -955,6 +955,8 @@ int pci_request_selected_regions_exclusive(struct pci_dev *, int, const char *);
 void pci_release_selected_regions(struct pci_dev *, int);
 
 /* drivers/pci/bus.c */
+struct pci_bus *pci_bus_get(struct pci_bus *bus);
+void pci_bus_put(struct pci_bus *bus);
 void pci_add_resource(struct list_head *resources, struct resource *res);
 void pci_add_resource_offset(struct list_head *resources, struct resource *res,
 			     resource_size_t offset);
-- 
1.7.9.5