Commit 97a1420d authored by Dan Williams's avatar Dan Williams Committed by James Bottomley
Browse files

[SCSI] libsas: dynamic queue depth 



The queue-depth for libsas-attached devices initializes to 32 and can
only be increased manually via sysfs to a max of 64, while mpt2sas
attached devices initialize to 254 and dynamically float via the
midlayer ->change_queue_depth interface.

No performance regression was observed with this change on the isci
driver.

Tested-by: default avatarDave Jiang <dave.jiang@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent f6e67035

drivers/scsi/libsas/sas_scsi_host.c

+18 −21
Original line number Diff line number Diff line
@@ -761,8 +761,7 @@ int sas_target_alloc(struct scsi_target *starget) 
	return 0;

}



#define SAS_DEF_QD 32

#define SAS_MAX_QD 64

#define SAS_DEF_QD 256



int sas_slave_configure(struct scsi_device *scsi_dev)

{
@@ -805,31 +804,29 @@ void sas_slave_destroy(struct scsi_device *scsi_dev) 
		dev->sata_dev.ap->link.device[0].class = ATA_DEV_NONE;

}



int sas_change_queue_depth(struct scsi_device *scsi_dev, int new_depth,

			   int reason)

int sas_change_queue_depth(struct scsi_device *sdev, int depth, int reason)

{

	struct domain_device *dev = sdev_to_domain_dev(scsi_dev);

	int res = min(new_depth, SAS_MAX_QD);

	struct domain_device *dev = sdev_to_domain_dev(sdev);



	if (dev_is_sata(dev))

		return __ata_change_queue_depth(dev->sata_dev.ap, scsi_dev,

						new_depth, reason);



	if (reason != SCSI_QDEPTH_DEFAULT)

		return __ata_change_queue_depth(dev->sata_dev.ap, sdev, depth,

						reason);



	switch (reason) {

	case SCSI_QDEPTH_DEFAULT:

	case SCSI_QDEPTH_RAMP_UP:

		if (!sdev->tagged_supported)

			depth = 1;

		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);

		break;

	case SCSI_QDEPTH_QFULL:

		scsi_track_queue_full(sdev, depth);

		break;

	default:

		return -EOPNOTSUPP;



	if (scsi_dev->tagged_supported)

		scsi_adjust_queue_depth(scsi_dev, scsi_get_tag_type(scsi_dev),

					res);

	else {

		sas_printk("device %llx LUN %x queue depth changed to 1\n",

			   SAS_ADDR(dev->sas_addr),

			   scsi_dev->lun);

		scsi_adjust_queue_depth(scsi_dev, 0, 1);

		res = 1;

	}



	return res;

	return depth;

}



int sas_change_queue_type(struct scsi_device *scsi_dev, int qt)

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