remove the "clustering" flag

remove the "clustering" flag

[Christoph Hellwig]

The block layer has been carrying around a magic clustering flag,
which is an artefact of prehistoric scsi layer design decisions.

Originally it controller if any segment merging happens at all for a
given LLLD, but with merging moving to the block layer and massively
more complex now it now essentically means that no segment shall be
larger than a page, and no segment shall cross a page boundary if
clustering is not enabled.  Unfortunately the SCSI layer historically
defaults to disabled clustering, but fortunately most drivers actually
enable it, and very few drivers do not set an explicit flag.

So this series first flips the default to be sensible, and then replaces
the magic flag with setting an explicit dma boundary and max segment
size to reuse the existing mechanisms.  It also fixes up a few drivers
where the no clustering setting was clearly bogus, although we can
probably lift these limits for others as well eventually.

[PATCH 1/9] scsi: flip the default on use_clustering

[Christoph Hellwig]

Most SCSI drivers want to enable "clustering", that is merging of
segments so that they might span more than a single page.  Remove the
ENABLE_CLUSTERING define, and require drivers to explicitly set
DISABLE_CLUSTERING to disable this feature.  All drivers not setting
use_clustering at all are switched to set DISABLE_CLUSTERING to keep
the current behavior.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/firewire/sbp2.c                         | 1 -
 drivers/infiniband/ulp/iser/iscsi_iser.c        | 1 -
 drivers/infiniband/ulp/srp/ib_srp.c             | 1 -
 drivers/message/fusion/mptfc.c                  | 1 -
 drivers/message/fusion/mptsas.c                 | 1 -
 drivers/message/fusion/mptspi.c                 | 1 -
 drivers/s390/scsi/zfcp_scsi.c                   | 1 -
 drivers/scsi/3w-9xxx.c                          | 1 -
 drivers/scsi/3w-sas.c                           | 1 -
 drivers/scsi/3w-xxxx.c                          | 1 -
 drivers/scsi/53c700.c                           | 1 -
 drivers/scsi/BusLogic.c                         | 1 -
 drivers/scsi/a100u2w.c                          | 1 -
 drivers/scsi/a3000.c                            | 1 -
 drivers/scsi/aacraid/linit.c                    | 1 -
 drivers/scsi/advansys.c                         | 8 --------
 drivers/scsi/aha1542.c                          | 1 -
 drivers/scsi/aha1740.c                          | 1 -
 drivers/scsi/aic7xxx/aic79xx_osm.c              | 1 -
 drivers/scsi/aic7xxx/aic7xxx_osm.c              | 1 -
 drivers/scsi/aic94xx/aic94xx_init.c             | 1 -
 drivers/scsi/arcmsr/arcmsr_hba.c                | 1 -
 drivers/scsi/arm/powertec.c                     | 1 -
 drivers/scsi/atp870u.c                          | 1 -
 drivers/scsi/be2iscsi/be_main.c                 | 1 -
 drivers/scsi/bfa/bfad_im.c                      | 2 --
 drivers/scsi/bnx2fc/bnx2fc_fcoe.c               | 1 -
 drivers/scsi/bnx2i/bnx2i_iscsi.c                | 1 -
 drivers/scsi/csiostor/csio_scsi.c               | 2 --
 drivers/scsi/cxlflash/main.c                    | 1 -
 drivers/scsi/dpt_i2o.c                          | 1 -
 drivers/scsi/esas2r/esas2r_main.c               | 1 -
 drivers/scsi/esp_scsi.c                         | 1 -
 drivers/scsi/fcoe/fcoe.c                        | 1 -
 drivers/scsi/fnic/fnic_main.c                   | 1 -
 drivers/scsi/gdth.c                             | 1 -
 drivers/scsi/hisi_sas/hisi_sas_v1_hw.c          | 1 -
 drivers/scsi/hisi_sas/hisi_sas_v2_hw.c          | 1 -
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c          | 1 -
 drivers/scsi/hpsa.c                             | 1 -
 drivers/scsi/hptiop.c                           | 1 -
 drivers/scsi/ibmvscsi/ibmvfc.c                  | 1 -
 drivers/scsi/ibmvscsi/ibmvscsi.c                | 1 -
 drivers/scsi/imm.c                              | 1 -
 drivers/scsi/initio.c                           | 1 -
 drivers/scsi/ipr.c                              | 1 -
 drivers/scsi/ips.c                              | 1 -
 drivers/scsi/isci/init.c                        | 1 -
 drivers/scsi/lpfc/lpfc_scsi.c                   | 4 ----
 drivers/scsi/megaraid.c                         | 1 -
 drivers/scsi/megaraid/megaraid_mbox.c           | 1 -
 drivers/scsi/megaraid/megaraid_sas_base.c       | 1 -
 drivers/scsi/mpt3sas/mpt3sas_scsih.c            | 2 --
 drivers/scsi/mvme147.c                          | 1 -
 drivers/scsi/mvsas/mv_init.c                    | 1 -
 drivers/scsi/mvumi.c                            | 1 +
 drivers/scsi/myrb.c                             | 1 +
 drivers/scsi/myrs.c                             | 1 +
 drivers/scsi/ncr53c8xx.c                        | 1 -
 drivers/scsi/pcmcia/sym53c500_cs.c              | 1 -
 drivers/scsi/pm8001/pm8001_init.c               | 1 -
 drivers/scsi/pmcraid.c                          | 1 -
 drivers/scsi/ppa.c                              | 1 -
 drivers/scsi/ps3rom.c                           | 1 -
 drivers/scsi/qedf/qedf_main.c                   | 1 -
 drivers/scsi/qedi/qedi_iscsi.c                  | 1 -
 drivers/scsi/qla1280.c                          | 1 -
 drivers/scsi/qla2xxx/qla_os.c                   | 1 -
 drivers/scsi/qla4xxx/ql4_os.c                   | 1 -
 drivers/scsi/qlogicpti.c                        | 1 -
 drivers/scsi/scsi_debug.c                       | 5 ++---
 drivers/scsi/scsi_lib.c                         | 2 +-
 drivers/scsi/smartpqi/smartpqi_init.c           | 1 -
 drivers/scsi/snic/snic_main.c                   | 1 -
 drivers/scsi/stex.c                             | 1 +
 drivers/scsi/storvsc_drv.c                      | 1 -
 drivers/scsi/sym53c8xx_2/sym_glue.c             | 1 -
 drivers/scsi/ufs/ufshcd.c                       | 1 +
 drivers/scsi/virtio_scsi.c                      | 1 -
 drivers/scsi/vmw_pvscsi.c                       | 1 -
 drivers/scsi/wd719x.c                           | 1 -
 drivers/staging/rts5208/rtsx.c                  | 6 ------
 drivers/staging/unisys/visorhba/visorhba_main.c | 1 -
 drivers/usb/image/microtek.c                    | 1 -
 drivers/usb/storage/scsiglue.c                  | 7 -------
 drivers/usb/storage/uas.c                       | 1 +
 include/linux/libata.h                          | 2 --
 include/scsi/scsi_host.h                        | 3 +--
 88 files changed, 10 insertions(+), 110 deletions(-)

diff --git a/drivers/firewire/sbp2.c b/drivers/firewire/sbp2.c
index 6bac03999fd4..09b845e90114 100644
--- a/drivers/firewire/sbp2.c
+++ b/drivers/firewire/sbp2.c
@@ -1610,7 +1610,6 @@ static struct scsi_host_template scsi_driver_template = {
 	.eh_abort_handler	= sbp2_scsi_abort,
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.can_queue		= 1,
 	.sdev_attrs		= sbp2_scsi_sysfs_attrs,
 };
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 3fecd87c9f2b..8c707accd148 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -997,7 +997,6 @@ static struct scsi_host_template iscsi_iser_sht = {
 	.eh_device_reset_handler= iscsi_eh_device_reset,
 	.eh_target_reset_handler = iscsi_eh_recover_target,
 	.target_alloc		= iscsi_target_alloc,
-	.use_clustering         = ENABLE_CLUSTERING,
 	.slave_alloc            = iscsi_iser_slave_alloc,
 	.proc_name              = "iscsi_iser",
 	.this_id                = -1,
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index eed0eb3bb04c..d27fe970ceba 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -3215,7 +3215,6 @@ static struct scsi_host_template srp_template = {
 	.can_queue			= SRP_DEFAULT_CMD_SQ_SIZE,
 	.this_id			= -1,
 	.cmd_per_lun			= SRP_DEFAULT_CMD_SQ_SIZE,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= srp_host_attrs,
 	.track_queue_depth		= 1,
 };
diff --git a/drivers/message/fusion/mptfc.c b/drivers/message/fusion/mptfc.c
index b15fdc626fb8..4314a3352b96 100644
--- a/drivers/message/fusion/mptfc.c
+++ b/drivers/message/fusion/mptfc.c
@@ -129,7 +129,6 @@ static struct scsi_host_template mptfc_driver_template = {
 	.sg_tablesize			= MPT_SCSI_SG_DEPTH,
 	.max_sectors			= 8192,
 	.cmd_per_lun			= 7,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= mptscsih_host_attrs,
 };
 
diff --git a/drivers/message/fusion/mptsas.c b/drivers/message/fusion/mptsas.c
index 9b404fc69c90..612cb5bc1333 100644
--- a/drivers/message/fusion/mptsas.c
+++ b/drivers/message/fusion/mptsas.c
@@ -1992,7 +1992,6 @@ static struct scsi_host_template mptsas_driver_template = {
 	.sg_tablesize			= MPT_SCSI_SG_DEPTH,
 	.max_sectors			= 8192,
 	.cmd_per_lun			= 7,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= mptscsih_host_attrs,
 	.no_write_same			= 1,
 };
diff --git a/drivers/message/fusion/mptspi.c b/drivers/message/fusion/mptspi.c
index 9a336a161d9f..7172b0b16bdd 100644
--- a/drivers/message/fusion/mptspi.c
+++ b/drivers/message/fusion/mptspi.c
@@ -848,7 +848,6 @@ static struct scsi_host_template mptspi_driver_template = {
 	.sg_tablesize			= MPT_SCSI_SG_DEPTH,
 	.max_sectors			= 8192,
 	.cmd_per_lun			= 7,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= mptscsih_host_attrs,
 };
 
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 82dbe2677fc1..689bfe1f5cec 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -425,7 +425,6 @@ static struct scsi_host_template zfcp_scsi_host_template = {
 				     * ZFCP_QDIO_MAX_SBALS_PER_REQ) - 2) * 8,
 				   /* GCD, adjusted later */
 	.dma_boundary		 = ZFCP_QDIO_SBALE_LEN - 1,
-	.use_clustering		 = 1,
 	.shost_attrs		 = zfcp_sysfs_shost_attrs,
 	.sdev_attrs		 = zfcp_sysfs_sdev_attrs,
 	.track_queue_depth	 = 1,
diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index 2d655a97b959..a3c20e3a8b7c 100644
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -1998,7 +1998,6 @@ static struct scsi_host_template driver_template = {
 	.sg_tablesize		= TW_APACHE_MAX_SGL_LENGTH,
 	.max_sectors		= TW_MAX_SECTORS,
 	.cmd_per_lun		= TW_MAX_CMDS_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= twa_host_attrs,
 	.emulated		= 1,
 	.no_write_same		= 1,
diff --git a/drivers/scsi/3w-sas.c b/drivers/scsi/3w-sas.c
index 480cf82700e9..e8f5f7c63190 100644
--- a/drivers/scsi/3w-sas.c
+++ b/drivers/scsi/3w-sas.c
@@ -1550,7 +1550,6 @@ static struct scsi_host_template driver_template = {
 	.sg_tablesize		= TW_LIBERATOR_MAX_SGL_LENGTH,
 	.max_sectors		= TW_MAX_SECTORS,
 	.cmd_per_lun		= TW_MAX_CMDS_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= twl_host_attrs,
 	.emulated		= 1,
 	.no_write_same		= 1,
diff --git a/drivers/scsi/3w-xxxx.c b/drivers/scsi/3w-xxxx.c
index a58257645e94..4938ba8adc86 100644
--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -2247,7 +2247,6 @@ static struct scsi_host_template driver_template = {
 	.sg_tablesize		= TW_MAX_SGL_LENGTH,
 	.max_sectors		= TW_MAX_SECTORS,
 	.cmd_per_lun		= TW_MAX_CMDS_PER_LUN,	
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= tw_host_attrs,
 	.emulated		= 1,
 	.no_write_same		= 1,
diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
index 6be77b3aa8a5..128d658d472a 100644
--- a/drivers/scsi/53c700.c
+++ b/drivers/scsi/53c700.c
@@ -318,7 +318,6 @@ NCR_700_detect(struct scsi_host_template *tpnt,
 	tpnt->can_queue = NCR_700_COMMAND_SLOTS_PER_HOST;
 	tpnt->sg_tablesize = NCR_700_SG_SEGMENTS;
 	tpnt->cmd_per_lun = NCR_700_CMD_PER_LUN;
-	tpnt->use_clustering = ENABLE_CLUSTERING;
 	tpnt->slave_configure = NCR_700_slave_configure;
 	tpnt->slave_destroy = NCR_700_slave_destroy;
 	tpnt->slave_alloc = NCR_700_slave_alloc;
diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c
index 9cee941f97d6..31afdfd73d41 100644
--- a/drivers/scsi/BusLogic.c
+++ b/drivers/scsi/BusLogic.c
@@ -3857,7 +3857,6 @@ static struct scsi_host_template blogic_template = {
 #endif
 	.unchecked_isa_dma = 1,
 	.max_sectors = 128,
-	.use_clustering = ENABLE_CLUSTERING,
 };
 
 /*
diff --git a/drivers/scsi/a100u2w.c b/drivers/scsi/a100u2w.c
index 00072ed9540b..ff53fd0d12f2 100644
--- a/drivers/scsi/a100u2w.c
+++ b/drivers/scsi/a100u2w.c
@@ -1078,7 +1078,6 @@ static struct scsi_host_template inia100_template = {
 	.can_queue		= 1,
 	.this_id		= 1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 };
 
 static int inia100_probe_one(struct pci_dev *pdev,
diff --git a/drivers/scsi/a3000.c b/drivers/scsi/a3000.c
index 2427a8541247..dcf435f312dd 100644
--- a/drivers/scsi/a3000.c
+++ b/drivers/scsi/a3000.c
@@ -175,7 +175,6 @@ static struct scsi_host_template amiga_a3000_scsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING
 };
 
 static int __init amiga_a3000_scsi_probe(struct platform_device *pdev)
diff --git a/drivers/scsi/aacraid/linit.c b/drivers/scsi/aacraid/linit.c
index 42defee90eb2..ecf91c827c17 100644
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -1540,7 +1540,6 @@ static struct scsi_host_template aac_driver_template = {
 #else
 	.cmd_per_lun			= AAC_NUM_IO_FIB,
 #endif
-	.use_clustering			= ENABLE_CLUSTERING,
 	.emulated			= 1,
 	.no_write_same			= 1,
 };
diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index 223ef6f4e258..95b4793c33f4 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -10808,14 +10808,6 @@ static struct scsi_host_template advansys_template = {
 	 * for non-ISA adapters.
 	 */
 	.unchecked_isa_dma = true,
-	/*
-	 * All adapters controlled by this driver are capable of large
-	 * scatter-gather lists. According to the mid-level SCSI documentation
-	 * this obviates any performance gain provided by setting
-	 * 'use_clustering'. But empirically while CPU utilization is increased
-	 * by enabling clustering, I/O throughput increases as well.
-	 */
-	.use_clustering = ENABLE_CLUSTERING,
 };
 
 static int advansys_wide_init_chip(struct Scsi_Host *shost)
diff --git a/drivers/scsi/aha1542.c b/drivers/scsi/aha1542.c
index a9c29757172f..ef38946bd1a2 100644
--- a/drivers/scsi/aha1542.c
+++ b/drivers/scsi/aha1542.c
@@ -1011,7 +1011,6 @@ static struct scsi_host_template driver_template = {
 	.this_id		= 7,
 	.sg_tablesize		= 16,
 	.unchecked_isa_dma	= 1, 
-	.use_clustering		= ENABLE_CLUSTERING,
 };
 
 static int aha1542_isa_match(struct device *pdev, unsigned int ndev)
diff --git a/drivers/scsi/aha1740.c b/drivers/scsi/aha1740.c
index 786bf7f32c64..da4150c17781 100644
--- a/drivers/scsi/aha1740.c
+++ b/drivers/scsi/aha1740.c
@@ -545,7 +545,6 @@ static struct scsi_host_template aha1740_template = {
 	.can_queue        = AHA1740_ECBS,
 	.this_id          = 7,
 	.sg_tablesize     = AHA1740_SCATTER,
-	.use_clustering   = ENABLE_CLUSTERING,
 	.eh_abort_handler = aha1740_eh_abort_handler,
 };
 
diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c b/drivers/scsi/aic7xxx/aic79xx_osm.c
index 2588b8f84ba0..57992519384e 100644
--- a/drivers/scsi/aic7xxx/aic79xx_osm.c
+++ b/drivers/scsi/aic7xxx/aic79xx_osm.c
@@ -920,7 +920,6 @@ struct scsi_host_template aic79xx_driver_template = {
 	.this_id		= -1,
 	.max_sectors		= 8192,
 	.cmd_per_lun		= 2,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.slave_alloc		= ahd_linux_slave_alloc,
 	.slave_configure	= ahd_linux_slave_configure,
 	.target_alloc		= ahd_linux_target_alloc,
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index c6be3aeb302b..3c9c17450bb3 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -807,7 +807,6 @@ struct scsi_host_template aic7xxx_driver_template = {
 	.this_id		= -1,
 	.max_sectors		= 8192,
 	.cmd_per_lun		= 2,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.slave_alloc		= ahc_linux_slave_alloc,
 	.slave_configure	= ahc_linux_slave_configure,
 	.target_alloc		= ahc_linux_target_alloc,
diff --git a/drivers/scsi/aic94xx/aic94xx_init.c b/drivers/scsi/aic94xx/aic94xx_init.c
index 41c4d8abdd4a..f83f79b07b50 100644
--- a/drivers/scsi/aic94xx/aic94xx_init.c
+++ b/drivers/scsi/aic94xx/aic94xx_init.c
@@ -68,7 +68,6 @@ static struct scsi_host_template aic94xx_sht = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler	= sas_eh_device_reset_handler,
 	.eh_target_reset_handler	= sas_eh_target_reset_handler,
 	.target_destroy		= sas_target_destroy,
diff --git a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
index 11e8e6df50b1..0f6751b0a633 100644
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -156,7 +156,6 @@ static struct scsi_host_template arcmsr_scsi_host_template = {
 	.sg_tablesize	        = ARCMSR_DEFAULT_SG_ENTRIES,
 	.max_sectors		= ARCMSR_MAX_XFER_SECTORS_C,
 	.cmd_per_lun		= ARCMSR_DEFAULT_CMD_PERLUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= arcmsr_host_attrs,
 	.no_write_same		= 1,
 };
diff --git a/drivers/scsi/arm/powertec.c b/drivers/scsi/arm/powertec.c
index 79aa88911b7f..759f95ba993c 100644
--- a/drivers/scsi/arm/powertec.c
+++ b/drivers/scsi/arm/powertec.c
@@ -294,7 +294,6 @@ static struct scsi_host_template powertecscsi_template = {
 	.sg_tablesize			= SG_MAX_SEGMENTS,
 	.dma_boundary			= IOMD_DMA_BOUNDARY,
 	.cmd_per_lun			= 2,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.proc_name			= "powertec",
 };
 
diff --git a/drivers/scsi/atp870u.c b/drivers/scsi/atp870u.c
index 802d15018ec0..1267200380f8 100644
--- a/drivers/scsi/atp870u.c
+++ b/drivers/scsi/atp870u.c
@@ -1681,7 +1681,6 @@ static struct scsi_host_template atp870u_template = {
      .can_queue         	= qcnt			/* can_queue */,
      .this_id           	= 7			/* SCSI ID */,
      .sg_tablesize      	= ATP870U_SCATTER	/*SG_ALL*/ /*SG_NONE*/,
-     .use_clustering    	= ENABLE_CLUSTERING,
      .max_sectors		= ATP870U_MAX_SECTORS,
 };
 
diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index effb6fc95af4..c4108b17d5ab 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -405,7 +405,6 @@ static struct scsi_host_template beiscsi_sht = {
 	.this_id = -1,
 	.max_sectors = BEISCSI_MAX_SECTORS,
 	.cmd_per_lun = BEISCSI_CMD_PER_LUN,
-	.use_clustering = ENABLE_CLUSTERING,
 	.vendor_id = SCSI_NL_VID_TYPE_PCI | BE_VENDOR_ID,
 	.track_queue_depth = 1,
 };
diff --git a/drivers/scsi/bfa/bfad_im.c b/drivers/scsi/bfa/bfad_im.c
index c4a33317d344..394930cbaa13 100644
--- a/drivers/scsi/bfa/bfad_im.c
+++ b/drivers/scsi/bfa/bfad_im.c
@@ -817,7 +817,6 @@ struct scsi_host_template bfad_im_scsi_host_template = {
 	.this_id = -1,
 	.sg_tablesize = BFAD_IO_MAX_SGE,
 	.cmd_per_lun = 3,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = bfad_im_host_attrs,
 	.max_sectors = BFAD_MAX_SECTORS,
 	.vendor_id = BFA_PCI_VENDOR_ID_BROCADE,
@@ -840,7 +839,6 @@ struct scsi_host_template bfad_im_vport_template = {
 	.this_id = -1,
 	.sg_tablesize = BFAD_IO_MAX_SGE,
 	.cmd_per_lun = 3,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = bfad_im_vport_attrs,
 	.max_sectors = BFAD_MAX_SECTORS,
 };
diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index cd160f2ec75d..63f76e20e229 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -2970,7 +2970,6 @@ static struct scsi_host_template bnx2fc_shost_template = {
 	.change_queue_depth	= scsi_change_queue_depth,
 	.this_id		= -1,
 	.cmd_per_lun		= 3,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.sg_tablesize		= BNX2FC_MAX_BDS_PER_CMD,
 	.max_sectors		= 1024,
 	.track_queue_depth	= 1,
diff --git a/drivers/scsi/bnx2i/bnx2i_iscsi.c b/drivers/scsi/bnx2i/bnx2i_iscsi.c
index de0a507577ef..69c75426c5eb 100644
--- a/drivers/scsi/bnx2i/bnx2i_iscsi.c
+++ b/drivers/scsi/bnx2i/bnx2i_iscsi.c
@@ -2263,7 +2263,6 @@ static struct scsi_host_template bnx2i_host_template = {
 	.max_sectors		= 127,
 	.cmd_per_lun		= 128,
 	.this_id		= -1,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.sg_tablesize		= ISCSI_MAX_BDS_PER_CMD,
 	.shost_attrs		= bnx2i_dev_attributes,
 	.track_queue_depth	= 1,
diff --git a/drivers/scsi/csiostor/csio_scsi.c b/drivers/scsi/csiostor/csio_scsi.c
index 8c15b7acb4b7..e67555effdb5 100644
--- a/drivers/scsi/csiostor/csio_scsi.c
+++ b/drivers/scsi/csiostor/csio_scsi.c
@@ -2280,7 +2280,6 @@ struct scsi_host_template csio_fcoe_shost_template = {
 	.this_id		= -1,
 	.sg_tablesize		= CSIO_SCSI_MAX_SGE,
 	.cmd_per_lun		= CSIO_MAX_CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= csio_fcoe_lport_attrs,
 	.max_sectors		= CSIO_MAX_SECTOR_SIZE,
 };
@@ -2300,7 +2299,6 @@ struct scsi_host_template csio_fcoe_shost_vport_template = {
 	.this_id		= -1,
 	.sg_tablesize		= CSIO_SCSI_MAX_SGE,
 	.cmd_per_lun		= CSIO_MAX_CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= csio_fcoe_vport_attrs,
 	.max_sectors		= CSIO_MAX_SECTOR_SIZE,
 };
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 6637116529aa..6996d15d1463 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -3180,7 +3180,6 @@ static struct scsi_host_template driver_template = {
 	.this_id = -1,
 	.sg_tablesize = 1,	/* No scatter gather support */
 	.max_sectors = CXLFLASH_MAX_SECTORS,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = cxlflash_host_attrs,
 	.sdev_attrs = cxlflash_dev_attrs,
 };
diff --git a/drivers/scsi/dpt_i2o.c b/drivers/scsi/dpt_i2o.c
index d5a474d1434f..70d1a18278af 100644
--- a/drivers/scsi/dpt_i2o.c
+++ b/drivers/scsi/dpt_i2o.c
@@ -3569,7 +3569,6 @@ static struct scsi_host_template driver_template = {
 	.slave_configure	= adpt_slave_configure,
 	.can_queue		= MAX_TO_IOP_MESSAGES,
 	.this_id		= 7,
-	.use_clustering		= ENABLE_CLUSTERING,
 };
 
 static int __init adpt_init(void)
diff --git a/drivers/scsi/esas2r/esas2r_main.c b/drivers/scsi/esas2r/esas2r_main.c
index c07118617d89..64397d441bae 100644
--- a/drivers/scsi/esas2r/esas2r_main.c
+++ b/drivers/scsi/esas2r/esas2r_main.c
@@ -250,7 +250,6 @@ static struct scsi_host_template driver_template = {
 		ESAS2R_DEFAULT_CMD_PER_LUN,
 	.present			= 0,
 	.unchecked_isa_dma		= 0,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.emulated			= 0,
 	.proc_name			= ESAS2R_DRVR_NAME,
 	.change_queue_depth		= scsi_change_queue_depth,
diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index ac7da9db7317..465df475f753 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -2676,7 +2676,6 @@ struct scsi_host_template scsi_esp_template = {
 	.can_queue		= 7,
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.max_sectors		= 0xffff,
 	.skip_settle_delay	= 1,
 };
diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index f46b312d04bc..4961ae442c87 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -286,7 +286,6 @@ static struct scsi_host_template fcoe_shost_template = {
 	.this_id = -1,
 	.cmd_per_lun = 3,
 	.can_queue = FCOE_MAX_OUTSTANDING_COMMANDS,
-	.use_clustering = ENABLE_CLUSTERING,
 	.sg_tablesize = SG_ALL,
 	.max_sectors = 0xffff,
 	.track_queue_depth = 1,
diff --git a/drivers/scsi/fnic/fnic_main.c b/drivers/scsi/fnic/fnic_main.c
index cc461fd7bef1..5b3534b0deda 100644
--- a/drivers/scsi/fnic/fnic_main.c
+++ b/drivers/scsi/fnic/fnic_main.c
@@ -115,7 +115,6 @@ static struct scsi_host_template fnic_host_template = {
 	.this_id = -1,
 	.cmd_per_lun = 3,
 	.can_queue = FNIC_DFLT_IO_REQ,
-	.use_clustering = ENABLE_CLUSTERING,
 	.sg_tablesize = FNIC_MAX_SG_DESC_CNT,
 	.max_sectors = 0xffff,
 	.shost_attrs = fnic_attrs,
diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c
index 16709735b546..194c294f9b6c 100644
--- a/drivers/scsi/gdth.c
+++ b/drivers/scsi/gdth.c
@@ -4680,7 +4680,6 @@ static struct scsi_host_template gdth_template = {
         .sg_tablesize           = GDTH_MAXSG,
         .cmd_per_lun            = GDTH_MAXC_P_L,
         .unchecked_isa_dma      = 1,
-        .use_clustering         = ENABLE_CLUSTERING,
 	.no_write_same		= 1,
 };
 
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
index d24342bcd072..3f4d72bc8e80 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
@@ -1817,7 +1817,6 @@ static struct scsi_host_template sht_v1_hw = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler = sas_eh_device_reset_handler,
 	.eh_target_reset_handler = sas_eh_target_reset_handler,
 	.target_destroy		= sas_target_destroy,
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
index e78a97e8c1c6..6b87975a92b0 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
@@ -3572,7 +3572,6 @@ static struct scsi_host_template sht_v2_hw = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler = sas_eh_device_reset_handler,
 	.eh_target_reset_handler = sas_eh_target_reset_handler,
 	.target_destroy		= sas_target_destroy,
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index 7e2b020c0c69..390f469e4f94 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -2226,7 +2226,6 @@ static struct scsi_host_template sht_v3_hw = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler = sas_eh_device_reset_handler,
 	.eh_target_reset_handler = sas_eh_target_reset_handler,
 	.target_destroy		= sas_target_destroy,
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index bc64e8a0449d..ff67ef5d5347 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -965,7 +965,6 @@ static struct scsi_host_template hpsa_driver_template = {
 	.scan_finished		= hpsa_scan_finished,
 	.change_queue_depth	= hpsa_change_queue_depth,
 	.this_id		= -1,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler = hpsa_eh_device_reset_handler,
 	.ioctl			= hpsa_ioctl,
 	.slave_alloc		= hpsa_slave_alloc,
diff --git a/drivers/scsi/hptiop.c b/drivers/scsi/hptiop.c
index dc52b37a0df8..3eedfd4f8f57 100644
--- a/drivers/scsi/hptiop.c
+++ b/drivers/scsi/hptiop.c
@@ -1180,7 +1180,6 @@ static struct scsi_host_template driver_template = {
 	.eh_host_reset_handler      = hptiop_reset,
 	.info                       = hptiop_info,
 	.emulated                   = 0,
-	.use_clustering             = ENABLE_CLUSTERING,
 	.proc_name                  = driver_name,
 	.shost_attrs                = hptiop_attrs,
 	.slave_configure            = hptiop_slave_config,
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index b64ca977825d..dbaa4f131433 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -3100,7 +3100,6 @@ static struct scsi_host_template driver_template = {
 	.this_id = -1,
 	.sg_tablesize = SG_ALL,
 	.max_sectors = IBMVFC_MAX_SECTORS,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = ibmvfc_attrs,
 	.track_queue_depth = 1,
 };
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 9df8a1a2299c..1135e74646e2 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2079,7 +2079,6 @@ static struct scsi_host_template driver_template = {
 	.can_queue = IBMVSCSI_MAX_REQUESTS_DEFAULT,
 	.this_id = -1,
 	.sg_tablesize = SG_ALL,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = ibmvscsi_attrs,
 };
 
diff --git a/drivers/scsi/imm.c b/drivers/scsi/imm.c
index 8c6627bc8a39..cea7f502e8ca 100644
--- a/drivers/scsi/imm.c
+++ b/drivers/scsi/imm.c
@@ -1110,7 +1110,6 @@ static struct scsi_host_template imm_template = {
 	.bios_param		= imm_biosparam,
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.can_queue		= 1,
 	.slave_alloc		= imm_adjust_queue,
 };
diff --git a/drivers/scsi/initio.c b/drivers/scsi/initio.c
index 0a8d786c84ed..eb2778b5c81b 100644
--- a/drivers/scsi/initio.c
+++ b/drivers/scsi/initio.c
@@ -2817,7 +2817,6 @@ static struct scsi_host_template initio_template = {
 	.can_queue		= MAX_TARGETS * i91u_MAXQUEUE,
 	.this_id		= 1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 };
 
 static int initio_probe_one(struct pci_dev *pdev,
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 271990bc065b..d1b4025a4503 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -6754,7 +6754,6 @@ static struct scsi_host_template driver_template = {
 	.sg_tablesize = IPR_MAX_SGLIST,
 	.max_sectors = IPR_IOA_MAX_SECTORS,
 	.cmd_per_lun = IPR_MAX_CMD_PER_LUN,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = ipr_ioa_attrs,
 	.sdev_attrs = ipr_dev_attrs,
 	.proc_name = IPR_NAME,
diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c
index 70a776dc0a02..067725295083 100644
--- a/drivers/scsi/ips.c
+++ b/drivers/scsi/ips.c
@@ -365,7 +365,6 @@ static struct scsi_host_template ips_driver_template = {
 	.this_id		= -1,
 	.sg_tablesize		= IPS_MAX_SG,
 	.cmd_per_lun		= 3,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.no_write_same		= 1,
 };
 
diff --git a/drivers/scsi/isci/init.c b/drivers/scsi/isci/init.c
index d72edbcbb7c6..68b90c4f79a3 100644
--- a/drivers/scsi/isci/init.c
+++ b/drivers/scsi/isci/init.c
@@ -163,7 +163,6 @@ static struct scsi_host_template isci_sht = {
 	.this_id			= -1,
 	.sg_tablesize			= SG_ALL,
 	.max_sectors			= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.eh_abort_handler		= sas_eh_abort_handler,
 	.eh_device_reset_handler        = sas_eh_device_reset_handler,
 	.eh_target_reset_handler        = sas_eh_target_reset_handler,
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 4fa6703a9ec9..6d5330e9b2a9 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -6036,7 +6036,6 @@ struct scsi_host_template lpfc_template_nvme = {
 	.this_id		= -1,
 	.sg_tablesize		= 1,
 	.cmd_per_lun		= 1,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= lpfc_hba_attrs,
 	.max_sectors		= 0xFFFF,
 	.vendor_id		= LPFC_NL_VENDOR_ID,
@@ -6061,7 +6060,6 @@ struct scsi_host_template lpfc_template_no_hr = {
 	.this_id		= -1,
 	.sg_tablesize		= LPFC_DEFAULT_SG_SEG_CNT,
 	.cmd_per_lun		= LPFC_CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= lpfc_hba_attrs,
 	.max_sectors		= 0xFFFF,
 	.vendor_id		= LPFC_NL_VENDOR_ID,
@@ -6088,7 +6086,6 @@ struct scsi_host_template lpfc_template = {
 	.this_id		= -1,
 	.sg_tablesize		= LPFC_DEFAULT_SG_SEG_CNT,
 	.cmd_per_lun		= LPFC_CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= lpfc_hba_attrs,
 	.max_sectors		= 0xFFFF,
 	.vendor_id		= LPFC_NL_VENDOR_ID,
@@ -6113,7 +6110,6 @@ struct scsi_host_template lpfc_vport_template = {
 	.this_id		= -1,
 	.sg_tablesize		= LPFC_DEFAULT_SG_SEG_CNT,
 	.cmd_per_lun		= LPFC_CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.shost_attrs		= lpfc_vport_attrs,
 	.max_sectors		= 0xFFFF,
 	.change_queue_depth	= scsi_change_queue_depth,
diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index 8c7154143a4e..4862f65ec3e8 100644
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -4148,7 +4148,6 @@ static struct scsi_host_template megaraid_template = {
 	.this_id			= DEFAULT_INITIATOR_ID,
 	.sg_tablesize			= MAX_SGLIST,
 	.cmd_per_lun			= DEF_CMD_PER_LUN,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.eh_abort_handler		= megaraid_abort,
 	.eh_device_reset_handler	= megaraid_reset,
 	.eh_bus_reset_handler		= megaraid_reset,
diff --git a/drivers/scsi/megaraid/megaraid_mbox.c b/drivers/scsi/megaraid/megaraid_mbox.c
index 3b7abe5ca7f5..77196a6c1de1 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.c
+++ b/drivers/scsi/megaraid/megaraid_mbox.c
@@ -336,7 +336,6 @@ static struct scsi_host_template megaraid_template_g = {
 	.eh_abort_handler		= megaraid_abort_handler,
 	.eh_host_reset_handler		= megaraid_reset_handler,
 	.change_queue_depth		= scsi_change_queue_depth,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.no_write_same			= 1,
 	.sdev_attrs			= megaraid_sdev_attrs,
 	.shost_attrs			= megaraid_shost_attrs,
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 9db7aebc3564..0c72c6e07bc3 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -3189,7 +3189,6 @@ static struct scsi_host_template megasas_template = {
 	.eh_timed_out = megasas_reset_timer,
 	.shost_attrs = megaraid_host_attrs,
 	.bios_param = megasas_bios_param,
-	.use_clustering = ENABLE_CLUSTERING,
 	.change_queue_depth = scsi_change_queue_depth,
 	.no_write_same = 1,
 };
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 5b9806d0719e..e4f92597647a 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -10173,7 +10173,6 @@ static struct scsi_host_template mpt2sas_driver_template = {
 	.sg_tablesize			= MPT2SAS_SG_DEPTH,
 	.max_sectors			= 32767,
 	.cmd_per_lun			= 7,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= mpt3sas_host_attrs,
 	.sdev_attrs			= mpt3sas_dev_attrs,
 	.track_queue_depth		= 1,
@@ -10212,7 +10211,6 @@ static struct scsi_host_template mpt3sas_driver_template = {
 	.sg_tablesize			= MPT3SAS_SG_DEPTH,
 	.max_sectors			= 32767,
 	.cmd_per_lun			= 7,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.shost_attrs			= mpt3sas_host_attrs,
 	.sdev_attrs			= mpt3sas_dev_attrs,
 	.track_queue_depth		= 1,
diff --git a/drivers/scsi/mvme147.c b/drivers/scsi/mvme147.c
index 7d1ab414b78f..ca96d6d9c350 100644
--- a/drivers/scsi/mvme147.c
+++ b/drivers/scsi/mvme147.c
@@ -78,7 +78,6 @@ static struct scsi_host_template mvme147_host_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= CMD_PER_LUN,
-	.use_clustering		= ENABLE_CLUSTERING
 };
 
 static struct Scsi_Host *mvme147_shost;
diff --git a/drivers/scsi/mvsas/mv_init.c b/drivers/scsi/mvsas/mv_init.c
index 3ac34373746c..030d911ee374 100644
--- a/drivers/scsi/mvsas/mv_init.c
+++ b/drivers/scsi/mvsas/mv_init.c
@@ -59,7 +59,6 @@ static struct scsi_host_template mvs_sht = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler = sas_eh_device_reset_handler,
 	.eh_target_reset_handler = sas_eh_target_reset_handler,
 	.target_destroy		= sas_target_destroy,
diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c
index 3d2d026d1ccf..d0c3f867fc58 100644
--- a/drivers/scsi/mvumi.c
+++ b/drivers/scsi/mvumi.c
@@ -2197,6 +2197,7 @@ static struct scsi_host_template mvumi_template = {
 	.eh_timed_out = mvumi_timed_out,
 	.eh_host_reset_handler = mvumi_host_reset,
 	.bios_param = mvumi_bios_param,
+	.use_clustering = DISABLE_CLUSTERING,
 	.this_id = -1,
 };
 
diff --git a/drivers/scsi/myrb.c b/drivers/scsi/myrb.c
index aeb282f617c5..f1abe38e3b3a 100644
--- a/drivers/scsi/myrb.c
+++ b/drivers/scsi/myrb.c
@@ -2236,6 +2236,7 @@ struct scsi_host_template myrb_template = {
 	.shost_attrs		= myrb_shost_attrs,
 	.sdev_attrs		= myrb_sdev_attrs,
 	.this_id		= -1,
+	.use_clustering		= DISABLE_CLUSTERING,
 };
 
 /**
diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c
index 0264a2e2bc19..f47b36382afa 100644
--- a/drivers/scsi/myrs.c
+++ b/drivers/scsi/myrs.c
@@ -1929,6 +1929,7 @@ struct scsi_host_template myrs_template = {
 	.shost_attrs		= myrs_shost_attrs,
 	.sdev_attrs		= myrs_sdev_attrs,
 	.this_id		= -1,
+	.use_clustering		= DISABLE_CLUSTERING,
 };
 
 static struct myrs_hba *myrs_alloc_host(struct pci_dev *pdev,
diff --git a/drivers/scsi/ncr53c8xx.c b/drivers/scsi/ncr53c8xx.c
index 6cd3e289ef99..1a236a3dfd51 100644
--- a/drivers/scsi/ncr53c8xx.c
+++ b/drivers/scsi/ncr53c8xx.c
@@ -8313,7 +8313,6 @@ struct Scsi_Host * __init ncr_attach(struct scsi_host_template *tpnt,
 	tpnt->this_id		= 7;
 	tpnt->sg_tablesize	= SCSI_NCR_SG_TABLESIZE;
 	tpnt->cmd_per_lun	= SCSI_NCR_CMD_PER_LUN;
-	tpnt->use_clustering	= ENABLE_CLUSTERING;
 
 	if (device->differential)
 		driver_setup.diff_support = device->differential;
diff --git a/drivers/scsi/pcmcia/sym53c500_cs.c b/drivers/scsi/pcmcia/sym53c500_cs.c
index a3b63bea0e50..d1e98a6ea28f 100644
--- a/drivers/scsi/pcmcia/sym53c500_cs.c
+++ b/drivers/scsi/pcmcia/sym53c500_cs.c
@@ -680,7 +680,6 @@ static struct scsi_host_template sym53c500_driver_template = {
      .can_queue			= 1,
      .this_id			= 7,
      .sg_tablesize		= 32,
-     .use_clustering		= ENABLE_CLUSTERING,
      .shost_attrs		= SYM53C500_shost_attrs
 };
 
diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index d71e7e4ec29c..a36060c23b37 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -84,7 +84,6 @@ static struct scsi_host_template pm8001_sht = {
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= SCSI_DEFAULT_MAX_SECTORS,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.eh_device_reset_handler = sas_eh_device_reset_handler,
 	.eh_target_reset_handler = sas_eh_target_reset_handler,
 	.target_destroy		= sas_target_destroy,
diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 707d766c1ee9..7c4673308f5b 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -4149,7 +4149,6 @@ static struct scsi_host_template pmcraid_host_template = {
 	.max_sectors = PMCRAID_IOA_MAX_SECTORS,
 	.no_write_same = 1,
 	.cmd_per_lun = PMCRAID_MAX_CMD_PER_LUN,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = pmcraid_host_attrs,
 	.proc_name = PMCRAID_DRIVER_NAME,
 };
diff --git a/drivers/scsi/ppa.c b/drivers/scsi/ppa.c
index ee86a0c62dbf..c182b5458f98 100644
--- a/drivers/scsi/ppa.c
+++ b/drivers/scsi/ppa.c
@@ -978,7 +978,6 @@ static struct scsi_host_template ppa_template = {
 	.bios_param		= ppa_biosparam,
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.can_queue		= 1,
 	.slave_alloc		= ppa_adjust_queue,
 };
diff --git a/drivers/scsi/ps3rom.c b/drivers/scsi/ps3rom.c
index 4924424d20fe..8d769138c01c 100644
--- a/drivers/scsi/ps3rom.c
+++ b/drivers/scsi/ps3rom.c
@@ -349,7 +349,6 @@ static struct scsi_host_template ps3rom_host_template = {
 	.sg_tablesize =		SG_ALL,
 	.emulated =             1,		/* only sg driver uses this */
 	.max_sectors =		PS3ROM_MAX_SECTORS,
-	.use_clustering =	ENABLE_CLUSTERING,
 	.module =		THIS_MODULE,
 };
 
diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
index d5a4f17fce51..e6ec6221dbf7 100644
--- a/drivers/scsi/qedf/qedf_main.c
+++ b/drivers/scsi/qedf/qedf_main.c
@@ -785,7 +785,6 @@ static struct scsi_host_template qedf_host_template = {
 	.name 		= QEDF_MODULE_NAME,
 	.this_id 	= -1,
 	.cmd_per_lun	= 32,
-	.use_clustering = ENABLE_CLUSTERING,
 	.max_sectors 	= 0xffff,
 	.queuecommand 	= qedf_queuecommand,
 	.shost_attrs	= qedf_host_attrs,
diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
index 2f0a4f2c5ff8..4da660c1c431 100644
--- a/drivers/scsi/qedi/qedi_iscsi.c
+++ b/drivers/scsi/qedi/qedi_iscsi.c
@@ -61,7 +61,6 @@ struct scsi_host_template qedi_host_template = {
 	.max_sectors = 0xffff,
 	.dma_boundary = QEDI_HW_DMA_BOUNDARY,
 	.cmd_per_lun = 128,
-	.use_clustering = ENABLE_CLUSTERING,
 	.shost_attrs = qedi_shost_attrs,
 };
 
diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c
index 9c5b67304a76..a414f51302b7 100644
--- a/drivers/scsi/qla1280.c
+++ b/drivers/scsi/qla1280.c
@@ -4203,7 +4203,6 @@ static struct scsi_host_template qla1280_driver_template = {
 	.can_queue		= MAX_OUTSTANDING_COMMANDS,
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= ENABLE_CLUSTERING,
 };
 
 
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 518f15141170..f20d14d40426 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -328,7 +328,6 @@ struct scsi_host_template qla2xxx_driver_template = {
 	.map_queues             = qla2xxx_map_queues,
 	.this_id		= -1,
 	.cmd_per_lun		= 3,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.sg_tablesize		= SG_ALL,
 
 	.max_sectors		= 0xFFFF,
diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index 1c702cd22359..949e186cc5d7 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -205,7 +205,6 @@ static struct scsi_host_template qla4xxx_driver_template = {
 
 	.this_id		= -1,
 	.cmd_per_lun		= 3,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.sg_tablesize		= SG_ALL,
 
 	.max_sectors		= 0xFFFF,
diff --git a/drivers/scsi/qlogicpti.c b/drivers/scsi/qlogicpti.c
index 9d09228eee28..e35ce762d454 100644
--- a/drivers/scsi/qlogicpti.c
+++ b/drivers/scsi/qlogicpti.c
@@ -1287,7 +1287,6 @@ static struct scsi_host_template qpti_template = {
 	.can_queue		= QLOGICPTI_REQ_QUEUE_LEN,
 	.this_id		= 7,
 	.sg_tablesize		= QLOGICPTI_MAX_SG(QLOGICPTI_REQ_QUEUE_LEN),
-	.use_clustering		= ENABLE_CLUSTERING,
 };
 
 static const struct of_device_id qpti_match[];
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 60bcc6df97a9..53ba417bef8a 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -5851,7 +5851,6 @@ static struct scsi_host_template sdebug_driver_template = {
 	.sg_tablesize =		SG_MAX_SEGMENTS,
 	.cmd_per_lun =		DEF_CMD_PER_LUN,
 	.max_sectors =		-1U,
-	.use_clustering = 	DISABLE_CLUSTERING,
 	.module =		THIS_MODULE,
 	.track_queue_depth =	1,
 };
@@ -5866,8 +5865,8 @@ static int sdebug_driver_probe(struct device *dev)
 	sdbg_host = to_sdebug_host(dev);
 
 	sdebug_driver_template.can_queue = sdebug_max_queue;
-	if (sdebug_clustering)
-		sdebug_driver_template.use_clustering = ENABLE_CLUSTERING;
+	if (!sdebug_clustering)
+		sdebug_driver_template.use_clustering = DISABLE_CLUSTERING;
 	hpnt = scsi_host_alloc(&sdebug_driver_template, sizeof(sdbg_host));
 	if (NULL == hpnt) {
 		pr_err("scsi_host_alloc failed\n");
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c7fccbb8f554..f6900e0b3024 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2229,7 +2229,7 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
 
 	blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
 
-	if (!shost->use_clustering)
+	if (shost->use_clustering == DISABLE_CLUSTERING)
 		q->limits.cluster = 0;
 
 	/*
diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index a25a07a0b7f0..c9a1a4973574 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -5779,7 +5779,6 @@ static struct scsi_host_template pqi_driver_template = {
 	.scan_start = pqi_scan_start,
 	.scan_finished = pqi_scan_finished,
 	.this_id = -1,
-	.use_clustering = ENABLE_CLUSTERING,
 	.eh_device_reset_handler = pqi_eh_device_reset_handler,
 	.ioctl = pqi_ioctl,
 	.slave_alloc = pqi_slave_alloc,
diff --git a/drivers/scsi/snic/snic_main.c b/drivers/scsi/snic/snic_main.c
index 5295277d6325..5e824fd6047a 100644
--- a/drivers/scsi/snic/snic_main.c
+++ b/drivers/scsi/snic/snic_main.c
@@ -127,7 +127,6 @@ static struct scsi_host_template snic_host_template = {
 	.this_id = -1,
 	.cmd_per_lun = SNIC_DFLT_QUEUE_DEPTH,
 	.can_queue = SNIC_MAX_IO_REQ,
-	.use_clustering = ENABLE_CLUSTERING,
 	.sg_tablesize = SNIC_MAX_SG_DESC_CNT,
 	.max_sectors = 0x800,
 	.shost_attrs = snic_attrs,
diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index 95f370ad05e0..af9078320d4b 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -1489,6 +1489,7 @@ static struct scsi_host_template driver_template = {
 	.eh_abort_handler		= stex_abort,
 	.eh_host_reset_handler		= stex_reset,
 	.this_id			= -1,
+	.use_clustering			= DISABLE_CLUSTERING,
 };
 
 static struct pci_device_id stex_pci_tbl[] = {
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index f03dc03a42c3..8ab05e93acfa 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1698,7 +1698,6 @@ static struct scsi_host_template scsi_driver = {
 	.slave_configure =	storvsc_device_configure,
 	.cmd_per_lun =		2048,
 	.this_id =		-1,
-	.use_clustering =	ENABLE_CLUSTERING,
 	/* Make sure we dont get a sg segment crosses a page boundary */
 	.dma_boundary =		PAGE_SIZE-1,
 	.no_write_same =	1,
diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 6e9b54061d7e..57f6d63e4c40 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -1660,7 +1660,6 @@ static struct scsi_host_template sym2_template = {
 	.eh_bus_reset_handler	= sym53c8xx_eh_bus_reset_handler,
 	.eh_host_reset_handler	= sym53c8xx_eh_host_reset_handler,
 	.this_id		= 7,
-	.use_clustering		= ENABLE_CLUSTERING,
 	.max_sectors		= 0xFFFF,
 #ifdef SYM_LINUX_PROC_INFO_SUPPORT
 	.show_info		= sym_show_info,
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b15f5dab0618..1b91240cd442 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6985,6 +6985,7 @@ static struct scsi_host_template ufshcd_driver_template = {
 	.max_host_blocked	= 1,
 	.track_queue_depth	= 1,
 	.sdev_groups		= ufshcd_driver_groups,
+	.use_clustering		= DISABLE_CLUSTERING,
 };
 
 static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 1c72db94270e..57c6c585226b 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -747,7 +747,6 @@ static struct scsi_host_template virtscsi_host_template = {
 	.slave_alloc = virtscsi_device_alloc,
 
 	.dma_boundary = UINT_MAX,
-	.use_clustering = ENABLE_CLUSTERING,
 	.target_alloc = virtscsi_target_alloc,
 	.target_destroy = virtscsi_target_destroy,
 	.map_queues = virtscsi_map_queues,
diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c
index 6e491023fdd8..644b0e1862b0 100644
--- a/drivers/scsi/vmw_pvscsi.c
+++ b/drivers/scsi/vmw_pvscsi.c
@@ -1007,7 +1007,6 @@ static struct scsi_host_template pvscsi_template = {
 	.sg_tablesize			= PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT,
 	.dma_boundary			= UINT_MAX,
 	.max_sectors			= 0xffff,
-	.use_clustering			= ENABLE_CLUSTERING,
 	.change_queue_depth		= pvscsi_change_queue_depth,
 	.eh_abort_handler		= pvscsi_abort,
 	.eh_device_reset_handler	= pvscsi_device_reset,
diff --git a/drivers/scsi/wd719x.c b/drivers/scsi/wd719x.c
index 808ba8e952db..e3310e9488d2 100644
--- a/drivers/scsi/wd719x.c
+++ b/drivers/scsi/wd719x.c
@@ -871,7 +871,6 @@ static struct scsi_host_template wd719x_template = {
 	.can_queue			= 255,
 	.this_id			= 7,
 	.sg_tablesize			= WD719X_SG,
-	.use_clustering			= ENABLE_CLUSTERING,
 };
 
 static int wd719x_pci_probe(struct pci_dev *pdev, const struct pci_device_id *d)
diff --git a/drivers/staging/rts5208/rtsx.c b/drivers/staging/rts5208/rtsx.c
index 69e6abe14abf..c57d66a7405f 100644
--- a/drivers/staging/rts5208/rtsx.c
+++ b/drivers/staging/rts5208/rtsx.c
@@ -237,12 +237,6 @@ static struct scsi_host_template rtsx_host_template = {
 	/* limit the total size of a transfer to 120 KB */
 	.max_sectors =                  240,
 
-	/* merge commands... this seems to help performance, but
-	 * periodically someone should test to see which setting is more
-	 * optimal.
-	 */
-	.use_clustering =		1,
-
 	/* emulated HBA */
 	.emulated =			1,
 
diff --git a/drivers/staging/unisys/visorhba/visorhba_main.c b/drivers/staging/unisys/visorhba/visorhba_main.c
index 4fc521c51c0e..5cf93e8eb77c 100644
--- a/drivers/staging/unisys/visorhba/visorhba_main.c
+++ b/drivers/staging/unisys/visorhba/visorhba_main.c
@@ -645,7 +645,6 @@ static struct scsi_host_template visorhba_driver_template = {
 	.this_id = -1,
 	.slave_alloc = visorhba_slave_alloc,
 	.slave_destroy = visorhba_slave_destroy,
-	.use_clustering = ENABLE_CLUSTERING,
 };
 
 /*
diff --git a/drivers/usb/image/microtek.c b/drivers/usb/image/microtek.c
index 9f2f563c82ed..607be1f4fe27 100644
--- a/drivers/usb/image/microtek.c
+++ b/drivers/usb/image/microtek.c
@@ -632,7 +632,6 @@ static struct scsi_host_template mts_scsi_host_template = {
 	.sg_tablesize =		SG_ALL,
 	.can_queue =		1,
 	.this_id =		-1,
-	.use_clustering =	1,
 	.emulated =		1,
 	.slave_alloc =		mts_slave_alloc,
 	.slave_configure =	mts_slave_configure,
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index e227bb5b794f..fde2e71a6ade 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -639,13 +639,6 @@ static const struct scsi_host_template usb_stor_host_template = {
 	 */
 	.max_sectors =                  240,
 
-	/*
-	 * merge commands... this seems to help performance, but
-	 * periodically someone should test to see which setting is more
-	 * optimal.
-	 */
-	.use_clustering =		1,
-
 	/* emulated HBA */
 	.emulated =			1,
 
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 1f7b401c4d04..6c75a0a50b3a 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -879,6 +879,7 @@ static struct scsi_host_template uas_host_template = {
 	.this_id = -1,
 	.sg_tablesize = SG_NONE,
 	.skip_settle_delay = 1,
+	.use_clustering = DISABLE_CLUSTERING,
 };
 
 #define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 38c95d66ab12..68133842e6d7 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -135,7 +135,6 @@ enum {
 
 	ATA_SHT_EMULATED	= 1,
 	ATA_SHT_THIS_ID		= -1,
-	ATA_SHT_USE_CLUSTERING	= 1,
 
 	/* struct ata_taskfile flags */
 	ATA_TFLAG_LBA48		= (1 << 0), /* enable 48-bit LBA and "HOB" */
@@ -1360,7 +1359,6 @@ extern struct device_attribute *ata_common_sdev_attrs[];
 	.tag_alloc_policy	= BLK_TAG_ALLOC_RR,		\
 	.this_id		= ATA_SHT_THIS_ID,		\
 	.emulated		= ATA_SHT_EMULATED,		\
-	.use_clustering		= ATA_SHT_USE_CLUSTERING,	\
 	.proc_name		= drv_name,			\
 	.slave_configure	= ata_scsi_slave_config,	\
 	.slave_destroy		= ata_scsi_slave_destroy,	\
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 5ea06d310a25..7dc534c794dc 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -44,8 +44,7 @@ struct blk_queue_tags;
 #define MODE_INITIATOR 0x01
 #define MODE_TARGET 0x02
 
-#define DISABLE_CLUSTERING 0
-#define ENABLE_CLUSTERING 1
+#define DISABLE_CLUSTERING (-1)
 
 struct scsi_host_template {
 	struct module *module;
-- 
2.19.1

Re: [PATCH 1/9] scsi: flip the default on use_clustering

[Bart Van Assche]

On Thu, 2018-12-06 at 07:52 -0800, Christoph Hellwig wrote:
> Most SCSI drivers want to enable "clustering", that is merging of
> segments so that they might span more than a single page.  Remove the
> ENABLE_CLUSTERING define, and require drivers to explicitly set
> DISABLE_CLUSTERING to disable this feature.  All drivers not setting
> use_clustering at all are switched to set DISABLE_CLUSTERING to keep
> the current behavior.

Was this patch produced manually or has it been generated with the help
of a script? In the latter case it would help if that script would be
included in the patch description.

Additionally, this patch would be much easier to review if it would be
split into two patches, one that adds .use_clustering = DISABLE_CLUSTERING
from SCSI templates that implicitly disable clustering and a second patch
that removes .use_clustering = ENABLE_CLUSTERING from all SCSI drivers.

Thanks,

Bart.

[PATCH 2/9] scsi: introduce a max_segment_size host_template parameters

[Christoph Hellwig]

This allows the host driver to indicate the maximum supported
segment size in a nice an easy way, so that the driver doesn't
have to worry about DMA-layer imposed limitations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/be2iscsi/be_main.c | 8 +-------
 drivers/scsi/hosts.c            | 5 +++++
 drivers/scsi/scsi_debug.c       | 2 +-
 drivers/scsi/scsi_lib.c         | 3 ++-
 include/scsi/scsi_host.h        | 6 ++++++
 5 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index c4108b17d5ab..39f3820572b4 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -214,12 +214,6 @@ static char const *cqe_desc[] = {
 	"CXN_KILLED_IMM_DATA_RCVD"
 };
 
-static int beiscsi_slave_configure(struct scsi_device *sdev)
-{
-	blk_queue_max_segment_size(sdev->request_queue, 65536);
-	return 0;
-}
-
 static int beiscsi_eh_abort(struct scsi_cmnd *sc)
 {
 	struct iscsi_task *abrt_task = (struct iscsi_task *)sc->SCp.ptr;
@@ -393,7 +387,6 @@ static struct scsi_host_template beiscsi_sht = {
 	.proc_name = DRV_NAME,
 	.queuecommand = iscsi_queuecommand,
 	.change_queue_depth = scsi_change_queue_depth,
-	.slave_configure = beiscsi_slave_configure,
 	.target_alloc = iscsi_target_alloc,
 	.eh_timed_out = iscsi_eh_cmd_timed_out,
 	.eh_abort_handler = beiscsi_eh_abort,
@@ -404,6 +397,7 @@ static struct scsi_host_template beiscsi_sht = {
 	.can_queue = BE2_IO_DEPTH,
 	.this_id = -1,
 	.max_sectors = BEISCSI_MAX_SECTORS,
+	.max_segment_size = 65536,
 	.cmd_per_lun = BEISCSI_CMD_PER_LUN,
 	.vendor_id = SCSI_NL_VID_TYPE_PCI | BE_VENDOR_ID,
 	.track_queue_depth = 1,
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index ea4b0bb0c1cd..e8148ba414a3 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -464,6 +464,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	else
 		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 
+	if (sht->max_segment_size)
+		shost->max_segment_size = sht->max_segment_size;
+	else
+		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
+
 	/*
 	 * assume a 4GB boundary, if not set
 	 */
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 53ba417bef8a..57d418d7d74e 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -3973,7 +3973,6 @@ static int scsi_debug_slave_configure(struct scsi_device *sdp)
 			return 1;  /* no resources, will be marked offline */
 	}
 	sdp->hostdata = devip;
-	blk_queue_max_segment_size(sdp->request_queue, -1U);
 	if (sdebug_no_uld)
 		sdp->no_uld_attach = 1;
 	config_cdb_len(sdp);
@@ -5851,6 +5850,7 @@ static struct scsi_host_template sdebug_driver_template = {
 	.sg_tablesize =		SG_MAX_SEGMENTS,
 	.cmd_per_lun =		DEF_CMD_PER_LUN,
 	.max_sectors =		-1U,
+	.max_segment_size =	-1U,
 	.module =		THIS_MODULE,
 	.track_queue_depth =	1,
 };
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f6900e0b3024..2d4fd6b4bd92 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2227,7 +2227,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
 	blk_queue_segment_boundary(q, shost->dma_boundary);
 	dma_set_seg_boundary(dev, shost->dma_boundary);
 
-	blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
+	blk_queue_max_segment_size(q,
+		min(shost->max_segment_size, dma_get_max_seg_size(dev)));
 
 	if (shost->use_clustering == DISABLE_CLUSTERING)
 		q->limits.cluster = 0;
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 7dc534c794dc..834204681ca3 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -364,6 +364,11 @@ struct scsi_host_template {
 	 */
 	unsigned int max_sectors;
 
+	/*
+	 * Maximum size in bytes of a single segment.
+	 */
+	unsigned int max_segment_size;
+
 	/*
 	 * DMA scatter gather segment boundary limit. A segment crossing this
 	 * boundary will be split in two.
@@ -603,6 +608,7 @@ struct Scsi_Host {
 	short unsigned int sg_tablesize;
 	short unsigned int sg_prot_tablesize;
 	unsigned int max_sectors;
+	unsigned int max_segment_size;
 	unsigned long dma_boundary;
 	/*
 	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
-- 
2.19.1

Re: [PATCH 2/9] scsi: introduce a max_segment_size host_template parameters

[Bart Van Assche]

On Thu, 2018-12-06 at 07:52 -0800, Christoph Hellwig wrote:
> This allows the host driver to indicate the maximum supported
> segment size in a nice an easy way, so that the driver doesn't
> have to worry about DMA-layer imposed limitations.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

Re: [PATCH 2/9] scsi: introduce a max_segment_size host_template parameters

[Ming Lei]

On Thu, Dec 06, 2018 at 07:52:51AM -0800, Christoph Hellwig wrote:
> This allows the host driver to indicate the maximum supported
> segment size in a nice an easy way, so that the driver doesn't
> have to worry about DMA-layer imposed limitations.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/scsi/be2iscsi/be_main.c | 8 +-------
>  drivers/scsi/hosts.c            | 5 +++++
>  drivers/scsi/scsi_debug.c       | 2 +-
>  drivers/scsi/scsi_lib.c         | 3 ++-
>  include/scsi/scsi_host.h        | 6 ++++++
>  5 files changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
> index c4108b17d5ab..39f3820572b4 100644
> --- a/drivers/scsi/be2iscsi/be_main.c
> +++ b/drivers/scsi/be2iscsi/be_main.c
> @@ -214,12 +214,6 @@ static char const *cqe_desc[] = {
>  	"CXN_KILLED_IMM_DATA_RCVD"
>  };
>  
> -static int beiscsi_slave_configure(struct scsi_device *sdev)
> -{
> -	blk_queue_max_segment_size(sdev->request_queue, 65536);
> -	return 0;
> -}
> -
>  static int beiscsi_eh_abort(struct scsi_cmnd *sc)
>  {
>  	struct iscsi_task *abrt_task = (struct iscsi_task *)sc->SCp.ptr;
> @@ -393,7 +387,6 @@ static struct scsi_host_template beiscsi_sht = {
>  	.proc_name = DRV_NAME,
>  	.queuecommand = iscsi_queuecommand,
>  	.change_queue_depth = scsi_change_queue_depth,
> -	.slave_configure = beiscsi_slave_configure,
>  	.target_alloc = iscsi_target_alloc,
>  	.eh_timed_out = iscsi_eh_cmd_timed_out,
>  	.eh_abort_handler = beiscsi_eh_abort,
> @@ -404,6 +397,7 @@ static struct scsi_host_template beiscsi_sht = {
>  	.can_queue = BE2_IO_DEPTH,
>  	.this_id = -1,
>  	.max_sectors = BEISCSI_MAX_SECTORS,
> +	.max_segment_size = 65536,
>  	.cmd_per_lun = BEISCSI_CMD_PER_LUN,
>  	.vendor_id = SCSI_NL_VID_TYPE_PCI | BE_VENDOR_ID,
>  	.track_queue_depth = 1,
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index ea4b0bb0c1cd..e8148ba414a3 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -464,6 +464,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
>  	else
>  		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
>  
> +	if (sht->max_segment_size)
> +		shost->max_segment_size = sht->max_segment_size;
> +	else
> +		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
> +
>  	/*
>  	 * assume a 4GB boundary, if not set
>  	 */
> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
> index 53ba417bef8a..57d418d7d74e 100644
> --- a/drivers/scsi/scsi_debug.c
> +++ b/drivers/scsi/scsi_debug.c
> @@ -3973,7 +3973,6 @@ static int scsi_debug_slave_configure(struct scsi_device *sdp)
>  			return 1;  /* no resources, will be marked offline */
>  	}
>  	sdp->hostdata = devip;
> -	blk_queue_max_segment_size(sdp->request_queue, -1U);
>  	if (sdebug_no_uld)
>  		sdp->no_uld_attach = 1;
>  	config_cdb_len(sdp);
> @@ -5851,6 +5850,7 @@ static struct scsi_host_template sdebug_driver_template = {
>  	.sg_tablesize =		SG_MAX_SEGMENTS,
>  	.cmd_per_lun =		DEF_CMD_PER_LUN,
>  	.max_sectors =		-1U,
> +	.max_segment_size =	-1U,
>  	.module =		THIS_MODULE,
>  	.track_queue_depth =	1,
>  };
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index f6900e0b3024..2d4fd6b4bd92 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2227,7 +2227,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
>  	blk_queue_segment_boundary(q, shost->dma_boundary);
>  	dma_set_seg_boundary(dev, shost->dma_boundary);
>  
> -	blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
> +	blk_queue_max_segment_size(q,
> +		min(shost->max_segment_size, dma_get_max_seg_size(dev)));
>  
>  	if (shost->use_clustering == DISABLE_CLUSTERING)
>  		q->limits.cluster = 0;
> diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
> index 7dc534c794dc..834204681ca3 100644
> --- a/include/scsi/scsi_host.h
> +++ b/include/scsi/scsi_host.h
> @@ -364,6 +364,11 @@ struct scsi_host_template {
>  	 */
>  	unsigned int max_sectors;
>  
> +	/*
> +	 * Maximum size in bytes of a single segment.
> +	 */
> +	unsigned int max_segment_size;
> +
>  	/*
>  	 * DMA scatter gather segment boundary limit. A segment crossing this
>  	 * boundary will be split in two.
> @@ -603,6 +608,7 @@ struct Scsi_Host {
>  	short unsigned int sg_tablesize;
>  	short unsigned int sg_prot_tablesize;
>  	unsigned int max_sectors;
> +	unsigned int max_segment_size;
>  	unsigned long dma_boundary;
>  	/*
>  	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
> -- 
> 2.19.1
> 

Just one concern, max segment size is often related with one specific
controller's DMA capability.

Is it possible that HBAs have different segment size, but all are driven
by same driver(shared scsi_host_template)?

If yes, this way may not be a correct abstract, at least defining 
'max_segment_size' from 'scsi_host_template'.

Thanks,
Ming

Re: [PATCH 2/9] scsi: introduce a max_segment_size host_template parameters

[Christoph Hellwig]

On Tue, Dec 11, 2018 at 10:02:38AM +0800, Ming Lei wrote:
> Just one concern, max segment size is often related with one specific
> controller's DMA capability.
> 
> Is it possible that HBAs have different segment size, but all are driven
> by same driver(shared scsi_host_template)?

It is support just like most other attributes - by having one variable
in the host template and one in the host, allowing the driver to
override the per-host one between scsi_host_alloc and scsi_add_host.

[PATCH 3/9] myrb: remove the DISABLE_CLUSTERING flag

[Christoph Hellwig]

The old DAC960 drivers was fine with merging over segment bondaries,
so this new driver should be to.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/myrb.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/scsi/myrb.c b/drivers/scsi/myrb.c
index f1abe38e3b3a..aeb282f617c5 100644
--- a/drivers/scsi/myrb.c
+++ b/drivers/scsi/myrb.c
@@ -2236,7 +2236,6 @@ struct scsi_host_template myrb_template = {
 	.shost_attrs		= myrb_shost_attrs,
 	.sdev_attrs		= myrb_sdev_attrs,
 	.this_id		= -1,
-	.use_clustering		= DISABLE_CLUSTERING,
 };
 
 /**
-- 
2.19.1

[PATCH 4/9] myrs: remove the DISABLE_CLUSTERING flag

[Christoph Hellwig]

The old DAC960 drivers was fine with merging over segment bondaries,
so this new driver should be to.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/myrs.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c
index f47b36382afa..0264a2e2bc19 100644
--- a/drivers/scsi/myrs.c
+++ b/drivers/scsi/myrs.c
@@ -1929,7 +1929,6 @@ struct scsi_host_template myrs_template = {
 	.shost_attrs		= myrs_shost_attrs,
 	.sdev_attrs		= myrs_sdev_attrs,
 	.this_id		= -1,
-	.use_clustering		= DISABLE_CLUSTERING,
 };
 
 static struct myrs_hba *myrs_alloc_host(struct pci_dev *pdev,
-- 
2.19.1

[PATCH 5/9] xen-scsifront: remove DISABLE_CLUSTERING

[Christoph Hellwig]

There is no such limitation in the protocol or implementation, so
remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/xen-scsifront.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index bb76d0d2022b..f0068e96a177 100644
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -696,7 +696,6 @@ static struct scsi_host_template scsifront_sht = {
 	.this_id		= -1,
 	.cmd_size		= sizeof(struct vscsifrnt_shadow),
 	.sg_tablesize		= VSCSIIF_SG_TABLESIZE,
-	.use_clustering		= DISABLE_CLUSTERING,
 	.proc_name		= "scsifront",
 };
 
-- 
2.19.1

[PATCH 6/9] mesh: remove DISABLE_CLUSTERING

[Christoph Hellwig]

mesh has no limitations on crossing pages for segments.  Just make
the 65535 byte segment size limit explicit, even if it matches the
current block layer limit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/mesh.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/mesh.c b/drivers/scsi/mesh.c
index ec6940f2fcb3..f3e182eb0970 100644
--- a/drivers/scsi/mesh.c
+++ b/drivers/scsi/mesh.c
@@ -1838,7 +1838,7 @@ static struct scsi_host_template mesh_template = {
 	.this_id			= 7,
 	.sg_tablesize			= SG_ALL,
 	.cmd_per_lun			= 2,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= 65535,
 };
 
 static int mesh_probe(struct macio_dev *mdev, const struct of_device_id *match)
-- 
2.19.1

Re: [PATCH 6/9] mesh: remove DISABLE_CLUSTERING

[Paul Mackerras]

On Thu, Dec 06, 2018 at 07:52:55AM -0800, Christoph Hellwig wrote:
> mesh has no limitations on crossing pages for segments.  Just make
> the 65535 byte segment size limit explicit, even if it matches the
> current block layer limit.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Tested-by: Paul Mackerras <paulus@ozlabs.org>

[PATCH 7/9] mac53c94: remove DISABLE_CLUSTERING

[Christoph Hellwig]

mac53c94 has no limitations on crossing pages for segments.  Just make
the 65535 byte segment size limit explicit, even if it matches the
current block layer limit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/mac53c94.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/mac53c94.c b/drivers/scsi/mac53c94.c
index 177701dfdfcb..c8e6ae98a4a6 100644
--- a/drivers/scsi/mac53c94.c
+++ b/drivers/scsi/mac53c94.c
@@ -403,7 +403,7 @@ static struct scsi_host_template mac53c94_template = {
 	.can_queue	= 1,
 	.this_id	= 7,
 	.sg_tablesize	= SG_ALL,
-	.use_clustering	= DISABLE_CLUSTERING,
+	.max_segment_size = 65535,
 };
 
 static int mac53c94_probe(struct macio_dev *mdev, const struct of_device_id *match)
-- 
2.19.1

Re: [PATCH 7/9] mac53c94: remove DISABLE_CLUSTERING

[Paul Mackerras]

On Thu, Dec 06, 2018 at 07:52:56AM -0800, Christoph Hellwig wrote:
> mac53c94 has no limitations on crossing pages for segments.  Just make
> the 65535 byte segment size limit explicit, even if it matches the
> current block layer limit.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Tested-by: Paul Mackerras <paulus@ozlabs.org>

[PATCH 8/9] scsi: remove the use_clustering flag

[Christoph Hellwig]

The same effects can be archived by setting the dma_boundary to
PAGE_SIZE - 1 and the max_segment_size to PAGE_SIZE, so shift those
settings into the drivers.  Note that in many cases the setting might
be bogus, but this keeps the status quo.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/scsi/scsi_mid_low_api.txt |  2 --
 arch/ia64/hp/sim/simscsi.c              |  3 ++-
 drivers/scsi/a2091.c                    |  3 ++-
 drivers/scsi/advansys.c                 |  4 ++--
 drivers/scsi/aha152x.c                  |  3 ++-
 drivers/scsi/arm/acornscsi.c            |  3 ++-
 drivers/scsi/arm/arxescsi.c             |  3 ++-
 drivers/scsi/arm/cumana_1.c             |  3 ++-
 drivers/scsi/arm/cumana_2.c             |  3 ++-
 drivers/scsi/arm/eesox.c                |  3 ++-
 drivers/scsi/arm/oak.c                  |  3 ++-
 drivers/scsi/atari_scsi.c               |  3 ++-
 drivers/scsi/cxgbi/cxgb3i/cxgb3i.c      |  3 ++-
 drivers/scsi/cxgbi/cxgb4i/cxgb4i.c      |  3 ++-
 drivers/scsi/dc395x.c                   |  3 ++-
 drivers/scsi/dmx3191d.c                 |  3 ++-
 drivers/scsi/g_NCR5380.c                |  3 ++-
 drivers/scsi/gvp11.c                    |  3 ++-
 drivers/scsi/hosts.c                    |  1 -
 drivers/scsi/ips.c                      |  1 -
 drivers/scsi/iscsi_tcp.c                |  3 ++-
 drivers/scsi/mac_esp.c                  |  3 ++-
 drivers/scsi/mac_scsi.c                 |  3 ++-
 drivers/scsi/mvumi.c                    |  3 ++-
 drivers/scsi/nsp32.c                    |  3 ++-
 drivers/scsi/pcmcia/nsp_cs.c            |  3 ++-
 drivers/scsi/pcmcia/qlogic_stub.c       |  3 ++-
 drivers/scsi/qlogicfas.c                |  3 ++-
 drivers/scsi/scsi_debug.c               |  6 ++++--
 drivers/scsi/scsi_lib.c                 |  3 ---
 drivers/scsi/sgiwd93.c                  |  3 ++-
 drivers/scsi/stex.c                     |  3 ++-
 drivers/scsi/sun3_scsi.c                |  3 ++-
 drivers/scsi/ufs/ufshcd.c               |  3 ++-
 drivers/target/loopback/tcm_loop.c      |  3 ++-
 drivers/usb/storage/uas.c               |  3 ++-
 include/scsi/scsi_host.h                | 13 -------------
 37 files changed, 66 insertions(+), 54 deletions(-)

diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt
index 177c031763c0..c1dd4939f4ae 100644
--- a/Documentation/scsi/scsi_mid_low_api.txt
+++ b/Documentation/scsi/scsi_mid_low_api.txt
@@ -1098,8 +1098,6 @@ of interest:
     unchecked_isa_dma - 1=>only use bottom 16 MB of ram (ISA DMA addressing
                    restriction), 0=>can use full 32 bit (or better) DMA
                    address space
-    use_clustering - 1=>SCSI commands in mid level's queue can be merged,
-                     0=>disallow SCSI command merging
     no_async_abort - 1=>Asynchronous aborts are not supported
                      0=>Timed-out commands will be aborted asynchronously
     hostt        - pointer to driver's struct scsi_host_template from which
diff --git a/arch/ia64/hp/sim/simscsi.c b/arch/ia64/hp/sim/simscsi.c
index 7e1426e76d96..d7206f97e9f4 100644
--- a/arch/ia64/hp/sim/simscsi.c
+++ b/arch/ia64/hp/sim/simscsi.c
@@ -347,7 +347,8 @@ static struct scsi_host_template driver_template = {
 	.sg_tablesize		= SG_ALL,
 	.max_sectors		= 1024,
 	.cmd_per_lun		= SIMSCSI_REQ_QUEUE_LEN,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static int __init
diff --git a/drivers/scsi/a2091.c b/drivers/scsi/a2091.c
index 61aadc7acb49..6cc9ab7fde6c 100644
--- a/drivers/scsi/a2091.c
+++ b/drivers/scsi/a2091.c
@@ -160,7 +160,8 @@ static struct scsi_host_template a2091_scsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= CMD_PER_LUN,
-	.use_clustering		= DISABLE_CLUSTERING
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static int a2091_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index 95b4793c33f4..d37584403c33 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -3192,8 +3192,8 @@ static void asc_prt_driver_conf(struct seq_file *m, struct Scsi_Host *shost)
 		   shost->sg_tablesize, shost->cmd_per_lun);
 
 	seq_printf(m,
-		   " unchecked_isa_dma %d, use_clustering %d\n",
-		   shost->unchecked_isa_dma, shost->use_clustering);
+		   " unchecked_isa_dma %d\n",
+		   shost->unchecked_isa_dma);
 
 	seq_printf(m,
 		   " flags 0x%x, last_reset 0x%lx, jiffies 0x%lx, asc_n_io_port 0x%x\n",
diff --git a/drivers/scsi/aha152x.c b/drivers/scsi/aha152x.c
index 301b3cad15f8..82b4668f04d6 100644
--- a/drivers/scsi/aha152x.c
+++ b/drivers/scsi/aha152x.c
@@ -2920,7 +2920,8 @@ static struct scsi_host_template aha152x_driver_template = {
 	.can_queue			= 1,
 	.this_id			= 7,
 	.sg_tablesize			= SG_ALL,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= PAGE_SIZE,
+	.dma_boundary			= PAGE_SIZE - 1,
 	.slave_alloc			= aha152x_adjust_queue,
 };
 
diff --git a/drivers/scsi/arm/acornscsi.c b/drivers/scsi/arm/acornscsi.c
index 421fe869a11e..9d9a9c9c11fc 100644
--- a/drivers/scsi/arm/acornscsi.c
+++ b/drivers/scsi/arm/acornscsi.c
@@ -2890,7 +2890,8 @@ static struct scsi_host_template acornscsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.proc_name		= "acornscsi",
 };
 
diff --git a/drivers/scsi/arm/arxescsi.c b/drivers/scsi/arm/arxescsi.c
index 3110736fd337..4650da9b303a 100644
--- a/drivers/scsi/arm/arxescsi.c
+++ b/drivers/scsi/arm/arxescsi.c
@@ -245,7 +245,8 @@ static struct scsi_host_template arxescsi_template = {
 	.can_queue			= 0,
 	.this_id			= 7,
 	.sg_tablesize			= SG_ALL,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= PAGE_SIZE,
+	.dma_boundary			= PAGE_SIZE - 1,
 	.proc_name			= "arxescsi",
 };
 
diff --git a/drivers/scsi/arm/cumana_1.c b/drivers/scsi/arm/cumana_1.c
index ae1d809904fb..6f8b32ec3e27 100644
--- a/drivers/scsi/arm/cumana_1.c
+++ b/drivers/scsi/arm/cumana_1.c
@@ -221,10 +221,11 @@ static struct scsi_host_template cumanascsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
 	.proc_name		= "CumanaSCSI-1",
 	.cmd_size		= NCR5380_CMD_SIZE,
 	.max_sectors		= 128,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static int cumanascsi1_probe(struct expansion_card *ec,
diff --git a/drivers/scsi/arm/cumana_2.c b/drivers/scsi/arm/cumana_2.c
index edce5f3cfdba..cbbc79bab6c3 100644
--- a/drivers/scsi/arm/cumana_2.c
+++ b/drivers/scsi/arm/cumana_2.c
@@ -367,7 +367,8 @@ static struct scsi_host_template cumanascsi2_template = {
 	.this_id			= 7,
 	.sg_tablesize			= SG_MAX_SEGMENTS,
 	.dma_boundary			= IOMD_DMA_BOUNDARY,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= PAGE_SIZE,
+	.dma_boundary			= PAGE_SIZE - 1,
 	.proc_name			= "cumanascsi2",
 };
 
diff --git a/drivers/scsi/arm/eesox.c b/drivers/scsi/arm/eesox.c
index e93e047f4316..7d069807f9fd 100644
--- a/drivers/scsi/arm/eesox.c
+++ b/drivers/scsi/arm/eesox.c
@@ -486,7 +486,8 @@ static struct scsi_host_template eesox_template = {
 	.this_id			= 7,
 	.sg_tablesize			= SG_MAX_SEGMENTS,
 	.dma_boundary			= IOMD_DMA_BOUNDARY,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= PAGE_SIZE,
+	.dma_boundary			= PAGE_SIZE - 1,
 	.proc_name			= "eesox",
 };
 
diff --git a/drivers/scsi/arm/oak.c b/drivers/scsi/arm/oak.c
index 05b7f755499b..961f8cf8b53d 100644
--- a/drivers/scsi/arm/oak.c
+++ b/drivers/scsi/arm/oak.c
@@ -110,7 +110,8 @@ static struct scsi_host_template oakscsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.proc_name		= "oakscsi",
 	.cmd_size		= NCR5380_CMD_SIZE,
 	.max_sectors		= 128,
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index 89f5154c40b6..e24147d8c1c1 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -714,7 +714,8 @@ static struct scsi_host_template atari_scsi_template = {
 	.eh_host_reset_handler	= atari_scsi_host_reset,
 	.this_id		= 7,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.cmd_size		= NCR5380_CMD_SIZE,
 };
 
diff --git a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
index bf07735275a4..94fd024fe70d 100644
--- a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
+++ b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
@@ -95,7 +95,8 @@ static struct scsi_host_template cxgb3i_host_template = {
 	.eh_device_reset_handler = iscsi_eh_device_reset,
 	.eh_target_reset_handler = iscsi_eh_recover_target,
 	.target_alloc	= iscsi_target_alloc,
-	.use_clustering	= DISABLE_CLUSTERING,
+	.max_segment_size = PAGE_SIZE,
+	.dma_boundary = PAGE_SIZE - 1,
 	.this_id	= -1,
 	.track_queue_depth = 1,
 };
diff --git a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
index 064ef5735182..66663037ff71 100644
--- a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
+++ b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
@@ -113,7 +113,8 @@ static struct scsi_host_template cxgb4i_host_template = {
 	.eh_device_reset_handler = iscsi_eh_device_reset,
 	.eh_target_reset_handler = iscsi_eh_recover_target,
 	.target_alloc	= iscsi_target_alloc,
-	.use_clustering	= DISABLE_CLUSTERING,
+	.max_segment_size = PAGE_SIZE,
+	.dma_boundary = PAGE_SIZE - 1,
 	.this_id	= -1,
 	.track_queue_depth = 1,
 };
diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index 8c55ec6e1827..4b29038ed8a4 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -4631,7 +4631,8 @@ static struct scsi_host_template dc395x_driver_template = {
 	.cmd_per_lun            = DC395x_MAX_CMD_PER_LUN,
 	.eh_abort_handler       = dc395x_eh_abort,
 	.eh_bus_reset_handler   = dc395x_eh_bus_reset,
-	.use_clustering         = DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 
diff --git a/drivers/scsi/dmx3191d.c b/drivers/scsi/dmx3191d.c
index 003c3d726238..ef07f3dbc290 100644
--- a/drivers/scsi/dmx3191d.c
+++ b/drivers/scsi/dmx3191d.c
@@ -63,7 +63,8 @@ static struct scsi_host_template dmx3191d_driver_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.cmd_size		= NCR5380_CMD_SIZE,
 };
 
diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index fc538181f8df..44f42194bbc2 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -700,7 +700,8 @@ static struct scsi_host_template driver_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.cmd_size		= NCR5380_CMD_SIZE,
 	.max_sectors		= 128,
 };
diff --git a/drivers/scsi/gvp11.c b/drivers/scsi/gvp11.c
index a27fc49ebd3a..2437da57afa8 100644
--- a/drivers/scsi/gvp11.c
+++ b/drivers/scsi/gvp11.c
@@ -184,7 +184,8 @@ static struct scsi_host_template gvp11_scsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= CMD_PER_LUN,
-	.use_clustering		= DISABLE_CLUSTERING
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static int check_wd33c93(struct gvp11_scsiregs *regs)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index e8148ba414a3..fce0b5d7119e 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -431,7 +431,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 	shost->cmd_per_lun = sht->cmd_per_lun;
 	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
-	shost->use_clustering = sht->use_clustering;
 	shost->no_write_same = sht->no_write_same;
 
 	if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c
index 067725295083..e8bc8d328bab 100644
--- a/drivers/scsi/ips.c
+++ b/drivers/scsi/ips.c
@@ -6677,7 +6677,6 @@ ips_register_scsi(int index)
 	sh->sg_tablesize = sh->hostt->sg_tablesize;
 	sh->can_queue = sh->hostt->can_queue;
 	sh->cmd_per_lun = sh->hostt->cmd_per_lun;
-	sh->use_clustering = sh->hostt->use_clustering;
 	sh->max_sectors = 128;
 
 	sh->max_id = ha->ntargets;
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 23354f206533..299c628e1065 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -980,7 +980,8 @@ static struct scsi_host_template iscsi_sw_tcp_sht = {
 	.eh_abort_handler       = iscsi_eh_abort,
 	.eh_device_reset_handler= iscsi_eh_device_reset,
 	.eh_target_reset_handler = iscsi_eh_recover_target,
-	.use_clustering         = DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.slave_alloc            = iscsi_sw_tcp_slave_alloc,
 	.slave_configure        = iscsi_sw_tcp_slave_configure,
 	.target_alloc		= iscsi_target_alloc,
diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c
index 764d320bb2ca..89cbb1fe28fb 100644
--- a/drivers/scsi/mac_esp.c
+++ b/drivers/scsi/mac_esp.c
@@ -307,7 +307,8 @@ static int esp_mac_probe(struct platform_device *dev)
 		goto fail;
 
 	host->max_id = 8;
-	host->use_clustering = DISABLE_CLUSTERING;
+	host->max_segment_size = PAGE_SIZE;
+	host->dma_boundary = PAGE_SIZE - 1;
 	esp = shost_priv(host);
 
 	esp->host = host;
diff --git a/drivers/scsi/mac_scsi.c b/drivers/scsi/mac_scsi.c
index dd6057359d7c..3b9838d46787 100644
--- a/drivers/scsi/mac_scsi.c
+++ b/drivers/scsi/mac_scsi.c
@@ -333,7 +333,8 @@ static struct scsi_host_template mac_scsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= 1,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.cmd_size		= NCR5380_CMD_SIZE,
 	.max_sectors		= 128,
 };
diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c
index d0c3f867fc58..85b0c9cf5658 100644
--- a/drivers/scsi/mvumi.c
+++ b/drivers/scsi/mvumi.c
@@ -2197,7 +2197,8 @@ static struct scsi_host_template mvumi_template = {
 	.eh_timed_out = mvumi_timed_out,
 	.eh_host_reset_handler = mvumi_host_reset,
 	.bios_param = mvumi_bios_param,
-	.use_clustering = DISABLE_CLUSTERING,
+	.max_segment_size = PAGE_SIZE,
+	.dma_boundary = PAGE_SIZE - 1,
 	.this_id = -1,
 };
 
diff --git a/drivers/scsi/nsp32.c b/drivers/scsi/nsp32.c
index 5aac3e801903..218b3b8c5c38 100644
--- a/drivers/scsi/nsp32.c
+++ b/drivers/scsi/nsp32.c
@@ -274,7 +274,8 @@ static struct scsi_host_template nsp32_template = {
 	.sg_tablesize			= NSP32_SG_SIZE,
 	.max_sectors			= 128,
 	.this_id			= NSP32_HOST_SCSIID,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= PAGE_SIZE,
+	.dma_boundary			= PAGE_SIZE - 1,
 	.eh_abort_handler		= nsp32_eh_abort,
 	.eh_host_reset_handler		= nsp32_eh_host_reset,
 /*	.highmem_io			= 1, */
diff --git a/drivers/scsi/pcmcia/nsp_cs.c b/drivers/scsi/pcmcia/nsp_cs.c
index f3230494a8c9..f6216985d199 100644
--- a/drivers/scsi/pcmcia/nsp_cs.c
+++ b/drivers/scsi/pcmcia/nsp_cs.c
@@ -86,7 +86,8 @@ static struct scsi_host_template nsp_driver_template = {
 	.can_queue		 = 1,
 	.this_id		 = NSP_INITIATOR_ID,
 	.sg_tablesize		 = SG_ALL,
-	.use_clustering		 = DISABLE_CLUSTERING,
+	.max_segment_size	 = PAGE_SIZE,
+	.dma_boundary		 = PAGE_SIZE - 1,
 };
 
 static nsp_hw_data nsp_data_base; /* attach <-> detect glue */
diff --git a/drivers/scsi/pcmcia/qlogic_stub.c b/drivers/scsi/pcmcia/qlogic_stub.c
index 173351a8554b..02115fd8d4b2 100644
--- a/drivers/scsi/pcmcia/qlogic_stub.c
+++ b/drivers/scsi/pcmcia/qlogic_stub.c
@@ -72,7 +72,8 @@ static struct scsi_host_template qlogicfas_driver_template = {
 	.can_queue		= 1,
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 /*====================================================================*/
diff --git a/drivers/scsi/qlogicfas.c b/drivers/scsi/qlogicfas.c
index 95431d605c24..6d26435118bf 100644
--- a/drivers/scsi/qlogicfas.c
+++ b/drivers/scsi/qlogicfas.c
@@ -193,7 +193,8 @@ static struct scsi_host_template qlogicfas_driver_template = {
 	.can_queue		= 1,
 	.this_id		= -1,
 	.sg_tablesize		= SG_ALL,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static __init int qlogicfas_init(void)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 57d418d7d74e..95a8244d23c2 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -5865,8 +5865,10 @@ static int sdebug_driver_probe(struct device *dev)
 	sdbg_host = to_sdebug_host(dev);
 
 	sdebug_driver_template.can_queue = sdebug_max_queue;
-	if (!sdebug_clustering)
-		sdebug_driver_template.use_clustering = DISABLE_CLUSTERING;
+	if (!sdebug_clustering) {
+		sdebug_driver_template.max_segment_size = PAGE_SIZE;
+		sdebug_driver_template.dma_boundary = PAGE_SIZE - 1;
+	}
 	hpnt = scsi_host_alloc(&sdebug_driver_template, sizeof(sdbg_host));
 	if (NULL == hpnt) {
 		pr_err("scsi_host_alloc failed\n");
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 2d4fd6b4bd92..966b7cfebdf8 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2230,9 +2230,6 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
 	blk_queue_max_segment_size(q,
 		min(shost->max_segment_size, dma_get_max_seg_size(dev)));
 
-	if (shost->use_clustering == DISABLE_CLUSTERING)
-		q->limits.cluster = 0;
-
 	/*
 	 * Set a reasonable default alignment:  The larger of 32-byte (dword),
 	 * which is a common minimum for HBAs, and the minimum DMA alignment,
diff --git a/drivers/scsi/sgiwd93.c b/drivers/scsi/sgiwd93.c
index 5ed696dc9bbd..ebbb723c39ef 100644
--- a/drivers/scsi/sgiwd93.c
+++ b/drivers/scsi/sgiwd93.c
@@ -208,7 +208,8 @@ static struct scsi_host_template sgiwd93_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_ALL,
 	.cmd_per_lun		= 8,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static int sgiwd93_probe(struct platform_device *pdev)
diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index af9078320d4b..4ed557686a78 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -1489,7 +1489,8 @@ static struct scsi_host_template driver_template = {
 	.eh_abort_handler		= stex_abort,
 	.eh_host_reset_handler		= stex_reset,
 	.this_id			= -1,
-	.use_clustering			= DISABLE_CLUSTERING,
+	.max_segment_size		= PAGE_SIZE,
+	.dma_boundary			= PAGE_SIZE - 1,
 };
 
 static struct pci_device_id stex_pci_tbl[] = {
diff --git a/drivers/scsi/sun3_scsi.c b/drivers/scsi/sun3_scsi.c
index 9492638296c8..f1f71e9f27e0 100644
--- a/drivers/scsi/sun3_scsi.c
+++ b/drivers/scsi/sun3_scsi.c
@@ -500,7 +500,8 @@ static struct scsi_host_template sun3_scsi_template = {
 	.this_id		= 7,
 	.sg_tablesize		= SG_NONE,
 	.cmd_per_lun		= 2,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.cmd_size		= NCR5380_CMD_SIZE,
 };
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1b91240cd442..0d8af787c479 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6985,7 +6985,8 @@ static struct scsi_host_template ufshcd_driver_template = {
 	.max_host_blocked	= 1,
 	.track_queue_depth	= 1,
 	.sdev_groups		= ufshcd_driver_groups,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 };
 
 static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index b0991e86587f..3a9252aeac8d 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -324,7 +324,8 @@ static struct scsi_host_template tcm_loop_driver_template = {
 	.sg_tablesize		= 256,
 	.cmd_per_lun		= 1024,
 	.max_sectors		= 0xFFFF,
-	.use_clustering		= DISABLE_CLUSTERING,
+	.max_segment_size	= PAGE_SIZE,
+	.dma_boundary		= PAGE_SIZE - 1,
 	.slave_alloc		= tcm_loop_slave_alloc,
 	.module			= THIS_MODULE,
 	.track_queue_depth	= 1,
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 6c75a0a50b3a..56dd16b2dd03 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -879,7 +879,8 @@ static struct scsi_host_template uas_host_template = {
 	.this_id = -1,
 	.sg_tablesize = SG_NONE,
 	.skip_settle_delay = 1,
-	.use_clustering = DISABLE_CLUSTERING,
+	.max_segment_size = PAGE_SIZE,
+	.dma_boundary = PAGE_SIZE - 1,
 };
 
 #define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 834204681ca3..7ba34a0ca8bf 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -44,8 +44,6 @@ struct blk_queue_tags;
 #define MODE_INITIATOR 0x01
 #define MODE_TARGET 0x02
 
-#define DISABLE_CLUSTERING (-1)
-
 struct scsi_host_template {
 	struct module *module;
 	const char *name;
@@ -418,16 +416,6 @@ struct scsi_host_template {
 	 */
 	unsigned unchecked_isa_dma:1;
 
-	/*
-	 * True if this host adapter can make good use of clustering.
-	 * I originally thought that if the tablesize was large that it
-	 * was a waste of CPU cycles to prepare a cluster list, but
-	 * it works out that the Buslogic is faster if you use a smaller
-	 * number of segments (i.e. use clustering).  I guess it is
-	 * inefficient.
-	 */
-	unsigned use_clustering:1;
-
 	/*
 	 * True for emulated SCSI host adapters (e.g. ATAPI).
 	 */
@@ -626,7 +614,6 @@ struct Scsi_Host {
 	
 	unsigned active_mode:2;
 	unsigned unchecked_isa_dma:1;
-	unsigned use_clustering:1;
 
 	/*
 	 * Host has requested that no further requests come through for the
-- 
2.19.1

Re: [PATCH 8/9] scsi: remove the use_clustering flag

[Bart Van Assche]

On Thu, 2018-12-06 at 07:52 -0800, Christoph Hellwig wrote:
> The same effects can be archived by setting the dma_boundary to
                          ^^^^^^^^
                          achieved?
> PAGE_SIZE - 1 and the max_segment_size to PAGE_SIZE, so shift those
> settings into the drivers.  Note that in many cases the setting might
> be bogus, but this keeps the status quo.
[ ... ]
>  Documentation/scsi/scsi_mid_low_api.txt |  2 --
>  arch/ia64/hp/sim/simscsi.c              |  3 ++-
>  drivers/scsi/a2091.c                    |  3 ++-
>  drivers/scsi/advansys.c                 |  4 ++--
>  drivers/scsi/aha152x.c                  |  3 ++-
>  drivers/scsi/arm/acornscsi.c            |  3 ++-
>  drivers/scsi/arm/arxescsi.c             |  3 ++-
>  drivers/scsi/arm/cumana_1.c             |  3 ++-
>  drivers/scsi/arm/cumana_2.c             |  3 ++-
>  drivers/scsi/arm/eesox.c                |  3 ++-
>  drivers/scsi/arm/oak.c                  |  3 ++-
>  drivers/scsi/atari_scsi.c               |  3 ++-
>  drivers/scsi/cxgbi/cxgb3i/cxgb3i.c      |  3 ++-
>  drivers/scsi/cxgbi/cxgb4i/cxgb4i.c      |  3 ++-
>  drivers/scsi/dc395x.c                   |  3 ++-
>  drivers/scsi/dmx3191d.c                 |  3 ++-
>  drivers/scsi/g_NCR5380.c                |  3 ++-
>  drivers/scsi/gvp11.c                    |  3 ++-
>  drivers/scsi/hosts.c                    |  1 -
>  drivers/scsi/ips.c                      |  1 -
>  drivers/scsi/iscsi_tcp.c                |  3 ++-
>  drivers/scsi/mac_esp.c                  |  3 ++-
>  drivers/scsi/mac_scsi.c                 |  3 ++-
>  drivers/scsi/mvumi.c                    |  3 ++-
>  drivers/scsi/nsp32.c                    |  3 ++-
>  drivers/scsi/pcmcia/nsp_cs.c            |  3 ++-
>  drivers/scsi/pcmcia/qlogic_stub.c       |  3 ++-
>  drivers/scsi/qlogicfas.c                |  3 ++-
>  drivers/scsi/scsi_debug.c               |  6 ++++--
>  drivers/scsi/scsi_lib.c                 |  3 ---
>  drivers/scsi/sgiwd93.c                  |  3 ++-
>  drivers/scsi/stex.c                     |  3 ++-
>  drivers/scsi/sun3_scsi.c                |  3 ++-
>  drivers/scsi/ufs/ufshcd.c               |  3 ++-
>  drivers/target/loopback/tcm_loop.c      |  3 ++-
>  drivers/usb/storage/uas.c               |  3 ++-
>  include/scsi/scsi_host.h                | 13 -------------
>  37 files changed, 66 insertions(+), 54 deletions(-)

Please split this patch into two patches: one that affects SCSI LLD drivers
and another patch that affects the SCSI core. That will make both reviewing
and bisecting easier.

Thanks,

Bart.

Re: [PATCH 8/9] scsi: remove the use_clustering flag

[Christoph Hellwig]

On Thu, Dec 06, 2018 at 09:13:24AM -0800, Bart Van Assche wrote:
> On Thu, 2018-12-06 at 07:52 -0800, Christoph Hellwig wrote:
> > The same effects can be archived by setting the dma_boundary to
>                           ^^^^^^^^
>                           achieved?
> > PAGE_SIZE - 1 and the max_segment_size to PAGE_SIZE, so shift those
> > settings into the drivers.  Note that in many cases the setting might
> > be bogus, but this keeps the status quo.
> [ ... ]
> >  Documentation/scsi/scsi_mid_low_api.txt |  2 --
> >  arch/ia64/hp/sim/simscsi.c              |  3 ++-
> >  drivers/scsi/a2091.c                    |  3 ++-
> >  drivers/scsi/advansys.c                 |  4 ++--
> >  drivers/scsi/aha152x.c                  |  3 ++-
> >  drivers/scsi/arm/acornscsi.c            |  3 ++-
> >  drivers/scsi/arm/arxescsi.c             |  3 ++-
> >  drivers/scsi/arm/cumana_1.c             |  3 ++-
> >  drivers/scsi/arm/cumana_2.c             |  3 ++-
> >  drivers/scsi/arm/eesox.c                |  3 ++-
> >  drivers/scsi/arm/oak.c                  |  3 ++-
> >  drivers/scsi/atari_scsi.c               |  3 ++-
> >  drivers/scsi/cxgbi/cxgb3i/cxgb3i.c      |  3 ++-
> >  drivers/scsi/cxgbi/cxgb4i/cxgb4i.c      |  3 ++-
> >  drivers/scsi/dc395x.c                   |  3 ++-
> >  drivers/scsi/dmx3191d.c                 |  3 ++-
> >  drivers/scsi/g_NCR5380.c                |  3 ++-
> >  drivers/scsi/gvp11.c                    |  3 ++-
> >  drivers/scsi/hosts.c                    |  1 -
> >  drivers/scsi/ips.c                      |  1 -
> >  drivers/scsi/iscsi_tcp.c                |  3 ++-
> >  drivers/scsi/mac_esp.c                  |  3 ++-
> >  drivers/scsi/mac_scsi.c                 |  3 ++-
> >  drivers/scsi/mvumi.c                    |  3 ++-
> >  drivers/scsi/nsp32.c                    |  3 ++-
> >  drivers/scsi/pcmcia/nsp_cs.c            |  3 ++-
> >  drivers/scsi/pcmcia/qlogic_stub.c       |  3 ++-
> >  drivers/scsi/qlogicfas.c                |  3 ++-
> >  drivers/scsi/scsi_debug.c               |  6 ++++--
> >  drivers/scsi/scsi_lib.c                 |  3 ---
> >  drivers/scsi/sgiwd93.c                  |  3 ++-
> >  drivers/scsi/stex.c                     |  3 ++-
> >  drivers/scsi/sun3_scsi.c                |  3 ++-
> >  drivers/scsi/ufs/ufshcd.c               |  3 ++-
> >  drivers/target/loopback/tcm_loop.c      |  3 ++-
> >  drivers/usb/storage/uas.c               |  3 ++-
> >  include/scsi/scsi_host.h                | 13 -------------
> >  37 files changed, 66 insertions(+), 54 deletions(-)
> 
> Please split this patch into two patches: one that affects SCSI LLD drivers
> and another patch that affects the SCSI core. That will make both reviewing
> and bisecting easier.

Just splitting it in two would not really help bisecting.  We could
split it into one per driver, but we rarely need to bisect which
driver is affected, as that usually is pretty obvious.

[PATCH 9/9] block: remove the cluster flag

[Christoph Hellwig]

Now that the the SCSI layer replaced the use of the cluster flag with
segment size limits and the DMA boundary we can remove the cluster
flag from the block layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-merge.c      | 18 +++++++-----------
 block/blk-settings.c   |  3 ---
 block/blk-sysfs.c      |  5 +----
 include/linux/blkdev.h |  6 ------
 4 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 6b5ad275ed56..4478d53cc6ee 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -194,7 +194,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
 			goto split;
 		}
 
-		if (bvprvp && blk_queue_cluster(q)) {
+		if (bvprvp) {
 			if (seg_size + bv.bv_len > queue_max_segment_size(q))
 				goto new_segment;
 			if (!biovec_phys_mergeable(q, bvprvp, &bv))
@@ -294,7 +294,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
 					     bool no_sg_merge)
 {
 	struct bio_vec bv, bvprv = { NULL };
-	int cluster, prev = 0;
+	int prev = 0;
 	unsigned int seg_size, nr_phys_segs;
 	struct bio *fbio, *bbio;
 	struct bvec_iter iter;
@@ -312,7 +312,6 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
 	}
 
 	fbio = bio;
-	cluster = blk_queue_cluster(q);
 	seg_size = 0;
 	nr_phys_segs = 0;
 	for_each_bio(bio) {
@@ -324,7 +323,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
 			if (no_sg_merge)
 				goto new_segment;
 
-			if (prev && cluster) {
+			if (prev) {
 				if (seg_size + bv.bv_len
 				    > queue_max_segment_size(q))
 					goto new_segment;
@@ -395,9 +394,6 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
 {
 	struct bio_vec end_bv = { NULL }, nxt_bv;
 
-	if (!blk_queue_cluster(q))
-		return 0;
-
 	if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
 	    queue_max_segment_size(q))
 		return 0;
@@ -414,12 +410,12 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
 static inline void
 __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
 		     struct scatterlist *sglist, struct bio_vec *bvprv,
-		     struct scatterlist **sg, int *nsegs, int *cluster)
+		     struct scatterlist **sg, int *nsegs)
 {
 
 	int nbytes = bvec->bv_len;
 
-	if (*sg && *cluster) {
+	if (*sg) {
 		if ((*sg)->length + nbytes > queue_max_segment_size(q))
 			goto new_segment;
 		if (!biovec_phys_mergeable(q, bvprv, bvec))
@@ -465,12 +461,12 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio,
 {
 	struct bio_vec bvec, bvprv = { NULL };
 	struct bvec_iter iter;
-	int cluster = blk_queue_cluster(q), nsegs = 0;
+	int nsegs = 0;
 
 	for_each_bio(bio)
 		bio_for_each_segment(bvec, bio, iter)
 			__blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg,
-					     &nsegs, &cluster);
+					     &nsegs);
 
 	return nsegs;
 }
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 696c04c1ab6c..9c8b62f8c180 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -109,7 +109,6 @@ void blk_set_default_limits(struct queue_limits *lim)
 	lim->alignment_offset = 0;
 	lim->io_opt = 0;
 	lim->misaligned = 0;
-	lim->cluster = 1;
 	lim->zoned = BLK_ZONED_NONE;
 }
 EXPORT_SYMBOL(blk_set_default_limits);
@@ -602,8 +601,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	t->io_min = max(t->io_min, b->io_min);
 	t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
 
-	t->cluster &= b->cluster;
-
 	/* Physical block size a multiple of the logical block size? */
 	if (t->physical_block_size & (t->logical_block_size - 1)) {
 		t->physical_block_size = t->logical_block_size;
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 844a454a7b3a..5144707f25ea 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -136,10 +136,7 @@ static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *
 
 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 {
-	if (blk_queue_cluster(q))
-		return queue_var_show(queue_max_segment_size(q), (page));
-
-	return queue_var_show(PAGE_SIZE, (page));
+	return queue_var_show(queue_max_segment_size(q), (page));
 }
 
 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4293dc1cd160..653ae90eec0b 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -389,7 +389,6 @@ struct queue_limits {
 
 	unsigned char		misaligned;
 	unsigned char		discard_misaligned;
-	unsigned char		cluster;
 	unsigned char		raid_partial_stripes_expensive;
 	enum blk_zoned_model	zoned;
 };
@@ -785,11 +784,6 @@ static inline bool queue_is_rq_based(struct request_queue *q)
 	return q->request_fn || q->mq_ops;
 }
 
-static inline unsigned int blk_queue_cluster(struct request_queue *q)
-{
-	return q->limits.cluster;
-}
-
 static inline enum blk_zoned_model
 blk_queue_zoned_model(struct request_queue *q)
 {
-- 
2.19.1