scsi: add new scsi-command flag for tagged commands

Currently scsi piggy backs on the block layer to define the concept
of a tagged command.  But we want to be able to have block-level host-wide
tags assigned even for untagged commands like the initial INQUIRY, so add
a new SCSI-level flag for commands that are tagged at the scsi level, so
that even commands without that set can have tags assigned to them.  Note
that this alredy is the case for the blk-mq code path, and this just lets
the old path catch up with it.

We also set this flag based upon sdev->simple_tags instead of the block
queue flag, so that it is entirely independent of the block layer tagging,
and thus always correct even if a driver doesn't use block level tagging
yet.

Also remove the old blk_rq_tagged; it was only used by SCSI drivers, and
removing it forces them to look for the proper replacement.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 38f8c85957b6..994eb083fff9 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1740,7 +1740,7 @@ static void scsi_request_fn(struct request_queue *q)
 		 * we add the dev to the starved list so it eventually gets
 		 * a run when a tag is freed.
 		 */
-		if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
+		if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
 			spin_lock_irq(shost->host_lock);
 			if (list_empty(&sdev->starved_entry))
 				list_add_tail(&sdev->starved_entry,
@@ -1754,6 +1754,11 @@ static void scsi_request_fn(struct request_queue *q)
 
 		if (!scsi_host_queue_ready(q, shost, sdev))
 			goto host_not_ready;
+	
+		if (sdev->simple_tags)
+			cmd->flags |= SCMD_TAGGED;
+		else
+			cmd->flags &= ~SCMD_TAGGED;
 
 		/*
 		 * Finally, initialize any error handling parameters, and set up
@@ -1908,10 +1913,10 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req,
 		blk_mq_start_request(req);
 	}
 
-	if (blk_queue_tagged(q))
-		req->cmd_flags |= REQ_QUEUED;
+	if (sdev->simple_tags)
+		cmd->flags |= SCMD_TAGGED;
 	else
-		req->cmd_flags &= ~REQ_QUEUED;
+		cmd->flags &= ~SCMD_TAGGED;
 
 	scsi_init_cmd_errh(cmd);
 	cmd->scsi_done = scsi_mq_done;