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Commit 2ecb204d authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

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: 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 e2eddf4d

Documentation/scsi/scsi_mid_low_api.txt

+1 −37
Original line number Diff line number Diff line
@@ -366,13 +366,11 @@ is initialized. The functions below are listed alphabetically and their 
names all start with "scsi_".



Summary:

   scsi_activate_tcq - turn on tag command queueing

   scsi_add_device - creates new scsi device (lu) instance

   scsi_add_host - perform sysfs registration and set up transport class

   scsi_adjust_queue_depth - change the queue depth on a SCSI device

   scsi_bios_ptable - return copy of block device's partition table

   scsi_block_requests - prevent further commands being queued to given host

   scsi_deactivate_tcq - turn off tag command queueing

   scsi_host_alloc - return a new scsi_host instance whose refcount==1

   scsi_host_get - increments Scsi_Host instance's refcount

   scsi_host_put - decrements Scsi_Host instance's refcount (free if 0)
@@ -389,24 +387,6 @@ Summary: 


Details:



/**

 * scsi_activate_tcq - turn on tag command queueing ("ordered" task attribute)

 * @sdev:       device to turn on TCQ for

 * @depth:      queue depth

 *

 *      Returns nothing

 *

 *      Might block: no

 *

 *      Notes: Eventually, it is hoped depth would be the maximum depth

 *      the device could cope with and the real queue depth

 *      would be adjustable from 0 to depth.

 *

 *      Defined (inline) in: include/scsi/scsi_tcq.h

 **/

void scsi_activate_tcq(struct scsi_device *sdev, int depth)





/**

 * scsi_add_device - creates new scsi device (lu) instance

 * @shost:   pointer to scsi host instance
@@ -471,9 +451,7 @@ int scsi_add_host(struct Scsi_Host *shost, struct device * dev) 
 *

 *      Notes: Can be invoked any time on a SCSI device controlled by this

 *      LLD. [Specifically during and after slave_configure() and prior to

 *      slave_destroy().] Can safely be invoked from interrupt code. Actual

 *      queue depth change may be delayed until the next command is being

 *      processed. See also scsi_activate_tcq() and scsi_deactivate_tcq().

 *      slave_destroy().] Can safely be invoked from interrupt code.

 *

 *      Defined in: drivers/scsi/scsi.c [see source code for more notes]

 *
@@ -514,20 +492,6 @@ unsigned char *scsi_bios_ptable(struct block_device *dev) 
void scsi_block_requests(struct Scsi_Host * shost)





/**

 * scsi_deactivate_tcq - turn off tag command queueing

 * @sdev:       device to turn off TCQ for

 * @depth:      queue depth (stored in sdev)

 *

 *      Returns nothing

 *

 *      Might block: no

 *

 *      Defined (inline) in: include/scsi/scsi_tcq.h

 **/

void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)





/**

 * scsi_host_alloc - create a scsi host adapter instance and perform basic

 *                   initialization.

drivers/message/fusion/mptsas.c

+1 −0
Original line number Diff line number Diff line
@@ -1994,6 +1994,7 @@ static struct scsi_host_template mptsas_driver_template = { 
	.cmd_per_lun			= 7,

	.use_clustering			= ENABLE_CLUSTERING,

	.shost_attrs			= mptscsih_host_attrs,

	.use_blk_tags			= 1,

};



static int mptsas_get_linkerrors(struct sas_phy *phy)

drivers/scsi/53c700.c

+5 −7
Original line number Diff line number Diff line
@@ -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);

	}

drivers/scsi/aic7xxx/aic79xx_osm.c

+6 −5
Original line number Diff line number Diff line
@@ -925,6 +925,7 @@ struct scsi_host_template aic79xx_driver_template = { 
	.slave_configure	= ahd_linux_slave_configure,

	.target_alloc		= ahd_linux_target_alloc,

	.target_destroy		= ahd_linux_target_destroy,

	.use_blk_tags		= 1,

};



/******************************** Bus DMA *************************************/
@@ -1468,12 +1469,12 @@ ahd_platform_set_tags(struct ahd_softc *ahd, struct scsi_device *sdev, 


	switch ((dev->flags & (AHD_DEV_Q_BASIC|AHD_DEV_Q_TAGGED))) {

	case AHD_DEV_Q_BASIC:

		scsi_set_tag_type(sdev, MSG_SIMPLE_TASK);

		scsi_activate_tcq(sdev, dev->openings + dev->active);

		scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TASK,

				dev->openings + dev->active);

		break;

	case AHD_DEV_Q_TAGGED:

		scsi_set_tag_type(sdev, MSG_ORDERED_TASK);

		scsi_activate_tcq(sdev, dev->openings + dev->active);

		scsi_adjust_queue_depth(sdev, MSG_ORDERED_TASK,

				dev->openings + dev->active);

		break;

	default:

		/*
@@ -1482,7 +1483,7 @@ ahd_platform_set_tags(struct ahd_softc *ahd, struct scsi_device *sdev, 
		 * serially on the controller/device.  This should

		 * remove some latency.

		 */

		scsi_deactivate_tcq(sdev, 1);

		scsi_adjust_queue_depth(sdev, 0, 1);

		break;

	}

}

drivers/scsi/aic7xxx/aic7xxx_osm.c

+6 −5
Original line number Diff line number Diff line
@@ -812,6 +812,7 @@ struct scsi_host_template aic7xxx_driver_template = { 
	.slave_configure	= ahc_linux_slave_configure,

	.target_alloc		= ahc_linux_target_alloc,

	.target_destroy		= ahc_linux_target_destroy,

	.use_blk_tags		= 1,

};



/**************************** Tasklet Handler *********************************/
@@ -1334,12 +1335,12 @@ ahc_platform_set_tags(struct ahc_softc *ahc, struct scsi_device *sdev, 
	}

	switch ((dev->flags & (AHC_DEV_Q_BASIC|AHC_DEV_Q_TAGGED))) {

	case AHC_DEV_Q_BASIC:

		scsi_set_tag_type(sdev, MSG_SIMPLE_TAG);

		scsi_activate_tcq(sdev, dev->openings + dev->active);

		scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TASK,

				dev->openings + dev->active);

		break;

	case AHC_DEV_Q_TAGGED:

		scsi_set_tag_type(sdev, MSG_ORDERED_TAG);

		scsi_activate_tcq(sdev, dev->openings + dev->active);

		scsi_adjust_queue_depth(sdev, MSG_ORDERED_TASK,

				dev->openings + dev->active);

		break;

	default:

		/*
@@ -1348,7 +1349,7 @@ ahc_platform_set_tags(struct ahc_softc *ahc, struct scsi_device *sdev, 
		 * serially on the controller/device.  This should

		 * remove some latency.

		 */

		scsi_deactivate_tcq(sdev, 2);

		scsi_adjust_queue_depth(sdev, 0, 2);

		break;

	}

}