We are about to remove the request pointer from struct scsi_cmnd and
that will complicate getting to the ref_tag via t10_pi_ref_tag() in
the various drivers. Introduce a helper function to retrieve the
reference tag so drivers will not have to worry about the details.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 include/scsi/scsi_cmnd.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 779a59fe8676..301b9cd4ddd0 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h

@@ -287,6 +287,13 @@ static inline sector_t scsi_get_lba(struct scsi_cmnd *scmd)
 	return blk_rq_pos(scmd->request);
 }
 
+static inline u32 scsi_prot_ref_tag(struct scsi_cmnd *scmd)
+{
+	struct request *rq = blk_mq_rq_from_pdu(scmd);
+
+	return t10_pi_ref_tag(rq);
+}
+
 static inline unsigned int scsi_prot_interval(struct scsi_cmnd *scmd)
 {
 	return scmd->device->sector_size;

-- 
2.31.1