1 files changed, 101 insertions, 0 deletions
diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
new file mode 100644
index 000000000..b27977e8a
--- /dev/null
+++ b/include/scsi/scsi_tcq.h
@@ -0,0 +1,101 @@
+#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
+static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
+						 int unique_tag)
+{
+	u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
+	struct request *req = NULL;
+
+	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(unique_tag));
+	return req ? (struct scsi_cmnd *)req->special : NULL;
+}
+
+/**
+ * scsi_find_tag - find a tagged command by device
+ * @SDpnt:	pointer to the ScSI device
+ * @tag:	tag generated by blk_mq_unique_tag()
+ *
+ * Notes:
+ *	Only works with tags allocated by the generic blk layer.
+ **/
+static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
+{
+        struct request *req;
+
+        if (tag != SCSI_NO_TAG) {
+		if (shost_use_blk_mq(sdev->host))
+			return scsi_mq_find_tag(sdev->host, tag);
+
+		req = blk_queue_find_tag(sdev->request_queue, tag);
+	        return req ? (struct scsi_cmnd *)req->special : NULL;
+	}
+
+	/* single command, look in space */
+	return sdev->current_cmnd;
+}
+
+
+/**
+ * scsi_init_shared_tag_map - create a shared tag map
+ * @shost:	the host to share the tag map among all devices
+ * @depth:	the total depth of the map
+ */
+static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
+{
+	/*
+	 * We always have a shared tag map around when using blk-mq.
+	 */
+	if (shost_use_blk_mq(shost))
+		return 0;
+
+	/*
+	 * If the shared tag map isn't already initialized, do it now.
+	 * This saves callers from having to check ->bqt when setting up
+	 * devices on the shared host (for libata)
+	 */
+	if (!shost->bqt) {
+		shost->bqt = blk_init_tags(depth,
+			shost->hostt->tag_alloc_policy);
+		if (!shost->bqt)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * scsi_host_find_tag - find the tagged command by host
+ * @shost:	pointer to scsi_host
+ * @tag:	tag generated by blk_mq_unique_tag()
+ *
+ * Notes:
+ *	Only works with tags allocated by the generic blk layer.
+ **/
+static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
+						int tag)
+{
+	struct request *req;
+
+	if (tag != SCSI_NO_TAG) {
+		if (shost_use_blk_mq(shost))
+			return scsi_mq_find_tag(shost, tag);
+		req = blk_map_queue_find_tag(shost->bqt, tag);
+		return req ? (struct scsi_cmnd *)req->special : NULL;
+	}
+	return NULL;
+}
+
+#endif /* CONFIG_BLOCK */
+#endif /* _SCSI_SCSI_TCQ_H */