scsi: don't set tagging state from scsi_adjust_queue_depth

Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth.  For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.

Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway.  The one other case looks
broken, but I've kept the behavior as-is for now.

Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.

Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 7bcace2..fce4e47 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -2700,11 +2700,8 @@
 	devip = devInfoReg(sdp);
 	if (NULL == devip)
 		return 1;	/* no resources, will be marked offline */
-	sdp->hostdata = devip;
 	sdp->tagged_supported = 1;
-	if (sdp->host->cmd_per_lun)
-		scsi_adjust_queue_depth(sdp, DEF_TAGGED_QUEUING,
-					DEF_CMD_PER_LUN);
+	sdp->hostdata = devip;
 	blk_queue_max_segment_size(sdp->request_queue, -1U);
 	if (scsi_debug_no_uld)
 		sdp->no_uld_attach = 1;
@@ -4494,7 +4491,7 @@
 		/* allow to exceed max host queued_arr elements for testing */
 		if (qdepth > SCSI_DEBUG_CANQUEUE + 10)
 			qdepth = SCSI_DEBUG_CANQUEUE + 10;
-		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), qdepth);
+		scsi_adjust_queue_depth(sdev, qdepth);
 	} else if (reason == SCSI_QDEPTH_QFULL)
 		scsi_track_queue_full(sdev, qdepth);
 	else