firewire: Move fw_card kref functions into linux/firewire.h

When writing a firewire driver that doesn't deal with struct fw_device
objects (e.g. it only publishes FireWire units and doesn't subscribe to
them), you likely need to keep referenced to struct fw_card objects so
that you can send messages to other nodes. This patch moves
fw_card_put(), fw_card_get() and fw_card_release() into the public
include/linux/firewire.h header instead of drivers/firewire/core.h, and
adds EXPORT_SYMBOL_GPL(fw_card_release).

The firewire-sbp-target module requires these so it can keep a reference
to the fw_card object in order that it can fetch ORBs to execute and
read/write related data and status information.

Signed-off-by: Chris Boot <[e-mail]>
Acked-by: Stefan Richter <[e-mail]>
Cc: Clemens Ladisch <[e-mail]>
Signed-off-by: Nicholas Bellinger <[e-mail]>

drivers/firewire/core-card.c

···
 
 	complete(&card->done);
 }
+EXPORT_SYMBOL_GPL(fw_card_release);
 
 void fw_core_remove_card(struct fw_card *card)
 {

drivers/firewire/core.h

···
 void fw_schedule_bus_reset(struct fw_card *card, bool delayed, bool short_reset);
 void fw_schedule_bm_work(struct fw_card *card, unsigned long delay);
 
-static inline struct fw_card *fw_card_get(struct fw_card *card)
-{
-	kref_get(&card->kref);
-
-	return card;
-}
-
-void fw_card_release(struct kref *kref);
-
-static inline void fw_card_put(struct fw_card *card)
-{
-	kref_put(&card->kref, fw_card_release);
-}
-
-
 /* -cdev */
 
 extern const struct file_operations fw_device_ops;

include/linux/firewire.h

···
 	__be32 maint_utility_register;
 };
 
+static inline struct fw_card *fw_card_get(struct fw_card *card)
+{
+	kref_get(&card->kref);
+
+	return card;
+}
+
+void fw_card_release(struct kref *kref);
+
+static inline void fw_card_put(struct fw_card *card)
+{
+	kref_put(&card->kref, fw_card_release);
+}
+
 struct fw_attribute_group {
 	struct attribute_group *groups[2];
 	struct attribute_group group;