[PATCH 1/6] Add refcount to sas_device struct

[Calvin Owens <calvinowens@fb.com>]

These objects can be referenced concurrently throughout the driver, we
need a way to make sure threads can't delete them out from under each
other.

Signed-off-by: Calvin Owens <calvinowens@fb.com>
---
 drivers/scsi/mpt2sas/mpt2sas_base.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.h b/drivers/scsi/mpt2sas/mpt2sas_base.h
index caff8d1..2e7dc33 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.h
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.h
@@ -376,8 +376,24 @@ struct _sas_device {
 	u8	phy;
 	u8	responding;
 	u8	pfa_led_on;
+	struct kref refcount;
 };
 
+static inline void sas_device_get(struct _sas_device *s)
+{
+	kref_get(&s->refcount);
+}
+
+static inline void sas_device_free(struct kref *r)
+{
+	kfree(container_of(r, struct _sas_device, refcount));
+}
+
+static inline void sas_device_put(struct _sas_device *s)
+{
+	kref_put(&s->refcount, sas_device_free);
+}
+
 /**
  * struct _raid_device - raid volume link list
  * @list: sas device list
-- 
1.8.1