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Commit 125c99bc authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
parent a62182f3

Documentation/block/biodoc.txt

+0 −4
Original line number Diff line number Diff line
@@ -827,10 +827,6 @@ but in the event of any barrier requests in the tag queue we need to ensure 
that requests are restarted in the order they were queue. This may happen

if the driver needs to use blk_queue_invalidate_tags().



Tagging also defines a new request flag, REQ_QUEUED. This is set whenever

a request is currently tagged. You should not use this flag directly,

blk_rq_tagged(rq) is the portable way to do so.



3.3 I/O Submission



The routine submit_bio() is used to submit a single io. Higher level i/o

block/blk-core.c

+2 −2
Original line number Diff line number Diff line
@@ -1266,7 +1266,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq) 
	blk_clear_rq_complete(rq);

	trace_block_rq_requeue(q, rq);



	if (blk_rq_tagged(rq))

	if (rq->cmd_flags & REQ_QUEUED)

		blk_queue_end_tag(q, rq);



	BUG_ON(blk_queued_rq(rq));
@@ -2554,7 +2554,7 @@ EXPORT_SYMBOL_GPL(blk_unprep_request); 
 */

void blk_finish_request(struct request *req, int error)

{

	if (blk_rq_tagged(req))

	if (req->cmd_flags & REQ_QUEUED)

		blk_queue_end_tag(req->q, req);



	BUG_ON(blk_queued_rq(req));

drivers/scsi/53c700.c

+3 −3
Original line number Diff line number Diff line
@@ -1767,7 +1767,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *) 
	 */

	if(NCR_700_get_depth(SCp->device) != 0

	   && (!(hostdata->tag_negotiated & (1<<scmd_id(SCp)))

	       || !blk_rq_tagged(SCp->request))) {

	       || !(SCp->flags & SCMD_TAGGED))) {

		CDEBUG(KERN_ERR, SCp, "has non zero depth %d\n",

		       NCR_700_get_depth(SCp->device));

		return SCSI_MLQUEUE_DEVICE_BUSY;
@@ -1795,7 +1795,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *) 
	printk("53c700: scsi%d, command ", SCp->device->host->host_no);

	scsi_print_command(SCp);

#endif

	if(blk_rq_tagged(SCp->request)

	if ((SCp->flags & SCMD_TAGGED)

	   && (hostdata->tag_negotiated &(1<<scmd_id(SCp))) == 0

	   && NCR_700_get_tag_neg_state(SCp->device) == NCR_700_START_TAG_NEGOTIATION) {

		scmd_printk(KERN_ERR, SCp, "Enabling Tag Command Queuing\n");
@@ -1809,7 +1809,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *) 
	 *

	 * FIXME: This will royally screw up on multiple LUN devices

	 * */

	if(!blk_rq_tagged(SCp->request)

	if (!(SCp->flags & SCMD_TAGGED)

	   && (hostdata->tag_negotiated &(1<<scmd_id(SCp)))) {

		scmd_printk(KERN_INFO, SCp, "Disabling Tag Command Queuing\n");

		hostdata->tag_negotiated &= ~(1<<scmd_id(SCp));

drivers/scsi/aic7xxx/aic7xxx_osm.c

+1 −1
Original line number Diff line number Diff line
@@ -1447,7 +1447,7 @@ ahc_linux_run_command(struct ahc_softc *ahc, struct ahc_linux_device *dev, 
	 * we are storing a full busy target *lun*

	 * table in SCB space.

	 */

	if (!blk_rq_tagged(cmd->request)

	if (!(cmd->flags & SCMD_TAGGED)

	    && (ahc->features & AHC_SCB_BTT) == 0) {

		int target_offset;

drivers/scsi/scsi_lib.c

+9 −4
Original line number Diff line number Diff line
@@ -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,
@@ -1755,6 +1755,11 @@ 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

		 * the timers for timeouts.
@@ -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;