v4.19.13 snapshot.
diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
new file mode 100644
index 0000000..e192a0c
--- /dev/null
+++ b/include/scsi/scsi_tcq.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SCSI_SCSI_TCQ_H
+#define _SCSI_SCSI_TCQ_H
+
+#include <linux/blkdev.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+#define SCSI_NO_TAG (-1) /* identify no tag in use */
+
+
+#ifdef CONFIG_BLOCK
+/**
+ * scsi_host_find_tag - find the tagged command by host
+ * @shost: pointer to scsi_host
+ * @tag: tag
+ *
+ * Note: for devices using multiple hardware queues tag must have been
+ * generated by blk_mq_unique_tag().
+ **/
+static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
+ int tag)
+{
+ struct request *req = NULL;
+
+ if (tag == SCSI_NO_TAG)
+ return NULL;
+
+ if (shost_use_blk_mq(shost)) {
+ u16 hwq = blk_mq_unique_tag_to_hwq(tag);
+
+ if (hwq < shost->tag_set.nr_hw_queues) {
+ req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
+ blk_mq_unique_tag_to_tag(tag));
+ }
+ } else {
+ req = blk_map_queue_find_tag(shost->bqt, tag);
+ }
+
+ if (!req)
+ return NULL;
+ return blk_mq_rq_to_pdu(req);
+}
+
+#endif /* CONFIG_BLOCK */
+#endif /* _SCSI_SCSI_TCQ_H */