firewire: move fw_device reference counting from drivers to core

fw_unit device drivers invariably need to talk to the fw_unit's parent
(an fw_device) and grandparent (an fw_card).  firewire-core already
maintains an fw_card reference for the entire lifetime of an fw_device.
Likewise, let firewire-core maintain an fw_device reference for the
entire lifetime of an fw_unit so that fw_unit drivers don't have to.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

2 files changed, 15 insertions, 0 deletions

diff --git a/drivers/firewire/core-device.c b/drivers/firewire/core-device.c
index f3b890da1e87..4c6c7d8cdaf1 100644
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -641,6 +641,7 @@ static void fw_unit_release(struct device *dev)
 {
 	struct fw_unit *unit = fw_unit(dev);
 
+	fw_device_put(fw_parent_device(unit));
 	kfree(unit);
 }
 
@@ -692,6 +693,7 @@ static void create_units(struct fw_device *device)
 		if (device_register(&unit->device) < 0)
 			goto skip_unit;
 
+		fw_device_get(device);
 		continue;
 
 	skip_unit:
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index b45be5767529..b5b34952cf16 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -1,6 +1,7 @@
 #ifndef _FIREWIRE_CORE_H
 #define _FIREWIRE_CORE_H
 
+#include <linux/device.h>
 #include <linux/fs.h>
 #include <linux/list.h>
 #include <linux/idr.h>
@@ -141,6 +142,18 @@ extern struct rw_semaphore fw_device_rwsem;
 extern struct idr fw_device_idr;
 extern int fw_cdev_major;
 
+static inline struct fw_device *fw_device_get(struct fw_device *device)
+{
+	get_device(&device->device);
+
+	return device;
+}
+
+static inline void fw_device_put(struct fw_device *device)
+{
+	put_device(&device->device);
+}
+
 struct fw_device *fw_device_get_by_devt(dev_t devt);
 int fw_device_set_broadcast_channel(struct device *dev, void *gen);
 void fw_node_event(struct fw_card *card, struct fw_node *node, int event);