scsi: always assign block layer tags if enabled

Allow a driver to ask for block layer tags by setting .use_blk_tags in the
host template, in which case it will always see a valid value in
request->tag, similar to the behavior when using blk-mq.  This means even
SCSI "untagged" commands will now have a tag, which is especially useful
when using a host-wide tag map.

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, 5 insertions, 7 deletions

diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
index 1b36fd3a6e62..497cbb1efd4b 100644
--- a/drivers/scsi/53c700.c
+++ b/drivers/scsi/53c700.c
@@ -327,6 +327,7 @@ NCR_700_detect(struct scsi_host_template *tpnt,
         tpnt->slave_alloc = NCR_700_slave_alloc;
         tpnt->change_queue_depth = NCR_700_change_queue_depth;
         tpnt->change_queue_type = NCR_700_change_queue_type;
+        tpnt->use_blk_tags = 1;
 
         if(tpnt->name == NULL)
                 tpnt->name = "53c700";
@@ -902,7 +903,7 @@ process_message(struct Scsi_Host *host,	struct NCR_700_Host_Parameters *hostdata
                         NCR_700_set_tag_neg_state(SCp->device, NCR_700_FINISHED_TAG_NEGOTIATION);
                         hostdata->tag_negotiated &= ~(1<<scmd_id(SCp));
                         SCp->device->tagged_supported = 0;
-                        scsi_deactivate_tcq(SCp->device, host->cmd_per_lun);
+                        scsi_adjust_queue_depth(SCp->device, 0, host->cmd_per_lun);
                 } else {
                         shost_printk(KERN_WARNING, host,
                                 "(%d:%d) Unexpected REJECT Message %s\n",
@@ -2049,8 +2050,7 @@ NCR_700_slave_configure(struct scsi_device *SDp)
 
         /* to do here: allocate memory; build a queue_full list */
         if(SDp->tagged_supported) {
-                scsi_set_tag_type(SDp, MSG_ORDERED_TAG);
-                scsi_activate_tcq(SDp, NCR_700_DEFAULT_TAGS);
+                scsi_adjust_queue_depth(SDp, MSG_ORDERED_TAG, NCR_700_DEFAULT_TAGS);
                 NCR_700_set_tag_neg_state(SDp, NCR_700_START_TAG_NEGOTIATION);
         } else {
                 /* initialise to default depth */
@@ -2094,8 +2094,6 @@ static int NCR_700_change_queue_type(struct scsi_device *SDp, int tag_type)
         struct NCR_700_Host_Parameters *hostdata = 
                 (struct NCR_700_Host_Parameters *)SDp->host->hostdata[0];
 
-        scsi_set_tag_type(SDp, tag_type);
-
         /* We have a global (per target) flag to track whether TCQ is
          * enabled, so we'll be turning it off for the entire target here.
          * our tag algorithm will fail if we mix tagged and untagged commands,
@@ -2106,12 +2104,12 @@ static int NCR_700_change_queue_type(struct scsi_device *SDp, int tag_type)
         if (!tag_type) {
                 /* shift back to the default unqueued number of commands
                  * (the user can still raise this) */
-                scsi_deactivate_tcq(SDp, SDp->host->cmd_per_lun);
+                scsi_adjust_queue_depth(SDp, 0, SDp->host->cmd_per_lun);
                 hostdata->tag_negotiated &= ~(1 << sdev_id(SDp));
         } else {
                 /* Here, we cleared the negotiation flag above, so this
                  * will force the driver to renegotiate */
-                scsi_activate_tcq(SDp, SDp->queue_depth);
+                scsi_adjust_queue_depth(SDp, tag_type, SDp->queue_depth);
                 if (change_tag)
                         NCR_700_set_tag_neg_state(SDp, NCR_700_START_TAG_NEGOTIATION);
         }