40 files changed, 18 insertions, 97 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index f2d2c7e2c76b..195ce7c12319 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1571,7 +1571,6 @@ static struct scsi_host_template srp_template = {
         .this_id                        = -1,
         .cmd_per_lun                    = SRP_SQ_SIZE,
         .use_clustering                 = ENABLE_CLUSTERING,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
         .shost_attrs                    = srp_host_attrs
 };
 
diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index 1c244832c6c8..b4912d1cee2a 100644
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -1990,7 +1990,6 @@ static struct scsi_host_template driver_template = {
         .max_sectors            = TW_MAX_SECTORS,
         .cmd_per_lun            = TW_MAX_CMDS_PER_LUN,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .shost_attrs            = twa_host_attrs,
         .emulated               = 1
 };
diff --git a/drivers/scsi/3w-xxxx.c b/drivers/scsi/3w-xxxx.c
index 59716ebeb10c..d09532162217 100644
--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -2261,7 +2261,6 @@ static struct scsi_host_template driver_template = {
         .max_sectors            = TW_MAX_SECTORS,
         .cmd_per_lun            = TW_MAX_CMDS_PER_LUN,  
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .shost_attrs            = tw_host_attrs,
         .emulated               = 1
 };
diff --git a/drivers/scsi/BusLogic.c b/drivers/scsi/BusLogic.c
index ead47c143ce0..4d3ebb1af490 100644
--- a/drivers/scsi/BusLogic.c
+++ b/drivers/scsi/BusLogic.c
@@ -3575,7 +3575,6 @@ static struct scsi_host_template Bus_Logic_template = {
         .unchecked_isa_dma = 1,
         .max_sectors = 128,
         .use_clustering = ENABLE_CLUSTERING,
-        .use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 /*
diff --git a/drivers/scsi/NCR53c406a.c b/drivers/scsi/NCR53c406a.c
index 137d065db3da..6961f78742ae 100644
--- a/drivers/scsi/NCR53c406a.c
+++ b/drivers/scsi/NCR53c406a.c
@@ -1065,7 +1065,6 @@ static struct scsi_host_template driver_template =
      .cmd_per_lun               = 1                     /* commands per lun */, 
      .unchecked_isa_dma         = 1                     /* unchecked_isa_dma */,
      .use_clustering            = ENABLE_CLUSTERING,
-     .use_sg_chaining           = ENABLE_SG_CHAINING,
 };
 
 #include "scsi_module.c"
diff --git a/drivers/scsi/a100u2w.c b/drivers/scsi/a100u2w.c
index d3a6d15fb77a..f608d4a1d6da 100644
--- a/drivers/scsi/a100u2w.c
+++ b/drivers/scsi/a100u2w.c
@@ -1071,7 +1071,6 @@ static struct scsi_host_template inia100_template = {
         .sg_tablesize           = SG_ALL,
         .cmd_per_lun            = 1,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 static int __devinit inia100_probe_one(struct pci_dev *pdev,
diff --git a/drivers/scsi/aacraid/linit.c b/drivers/scsi/aacraid/linit.c
index 61be22774e99..0e8267c1e915 100644
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -1032,7 +1032,6 @@ static struct scsi_host_template aac_driver_template = {
         .cmd_per_lun                    = AAC_NUM_IO_FIB,
 #endif
         .use_clustering                 = ENABLE_CLUSTERING,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
         .emulated                       = 1,
 };
 
diff --git a/drivers/scsi/aha1740.c b/drivers/scsi/aha1740.c
index be58a0b097c7..7c45d88a205b 100644
--- a/drivers/scsi/aha1740.c
+++ b/drivers/scsi/aha1740.c
@@ -563,7 +563,6 @@ static struct scsi_host_template aha1740_template = {
         .sg_tablesize     = AHA1740_SCATTER,
         .cmd_per_lun      = AHA1740_CMDLUN,
         .use_clustering   = ENABLE_CLUSTERING,
-        .use_sg_chaining  = ENABLE_SG_CHAINING,
         .eh_abort_handler = aha1740_eh_abort_handler,
 };
 
diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c b/drivers/scsi/aic7xxx/aic79xx_osm.c
index 3c4efa4ae543..014654792901 100644
--- a/drivers/scsi/aic7xxx/aic79xx_osm.c
+++ b/drivers/scsi/aic7xxx/aic79xx_osm.c
@@ -766,7 +766,6 @@ struct scsi_host_template aic79xx_driver_template = {
         .max_sectors            = 8192,
         .cmd_per_lun            = 2,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .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 bff7f8c59856..99a3b33a3233 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -747,7 +747,6 @@ struct scsi_host_template aic7xxx_driver_template = {
         .max_sectors            = 8192,
         .cmd_per_lun            = 2,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .slave_alloc            = ahc_linux_slave_alloc,
         .slave_configure        = ahc_linux_slave_configure,
         .target_alloc           = ahc_linux_target_alloc,
diff --git a/drivers/scsi/aic7xxx_old.c b/drivers/scsi/aic7xxx_old.c
index bcb0b870320c..3bfd9296bbfa 100644
--- a/drivers/scsi/aic7xxx_old.c
+++ b/drivers/scsi/aic7xxx_old.c
@@ -11141,7 +11141,6 @@ static struct scsi_host_template driver_template = {
         .max_sectors            = 2048,
         .cmd_per_lun            = 3,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 #include "scsi_module.c"
diff --git a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
index d80dba913a75..f4a202e8df26 100644
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -122,7 +122,6 @@ static struct scsi_host_template arcmsr_scsi_host_template = {
         .max_sectors            = ARCMSR_MAX_XFER_SECTORS,
         .cmd_per_lun            = ARCMSR_MAX_CMD_PERLUN,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .shost_attrs            = arcmsr_host_attrs,
 };
 #ifdef CONFIG_SCSI_ARCMSR_AER
diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index f93c73c0ba53..22ef3716e786 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -4763,7 +4763,6 @@ static struct scsi_host_template dc395x_driver_template = {
         .eh_bus_reset_handler   = dc395x_eh_bus_reset,
         .unchecked_isa_dma      = 0,
         .use_clustering         = DISABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 
diff --git a/drivers/scsi/dpt_i2o.c b/drivers/scsi/dpt_i2o.c
index 19cce125124c..c9dd8392aab2 100644
--- a/drivers/scsi/dpt_i2o.c
+++ b/drivers/scsi/dpt_i2o.c
@@ -3340,7 +3340,6 @@ static struct scsi_host_template driver_template = {
         .this_id                = 7,
         .cmd_per_lun            = 1,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 #include "scsi_module.c"
 MODULE_LICENSE("GPL");
diff --git a/drivers/scsi/eata.c b/drivers/scsi/eata.c
index 05163cefec12..8be3d76656fa 100644
--- a/drivers/scsi/eata.c
+++ b/drivers/scsi/eata.c
@@ -524,7 +524,6 @@ static struct scsi_host_template driver_template = {
         .this_id = 7,
         .unchecked_isa_dma = 1,
         .use_clustering = ENABLE_CLUSTERING,
-        .use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 #if !defined(__BIG_ENDIAN_BITFIELD) && !defined(__LITTLE_ENDIAN_BITFIELD)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5ea1f986220c..880c78bff0e1 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -342,7 +342,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
         shost->use_clustering = sht->use_clustering;
         shost->ordered_tag = sht->ordered_tag;
         shost->active_mode = sht->supported_mode;
-        shost->use_sg_chaining = sht->use_sg_chaining;
 
         if (sht->supported_mode == MODE_UNKNOWN)
                 /* means we didn't set it ... default to INITIATOR */
diff --git a/drivers/scsi/hptiop.c b/drivers/scsi/hptiop.c
index 890f44fa0e1a..ff149ad6bc4e 100644
--- a/drivers/scsi/hptiop.c
+++ b/drivers/scsi/hptiop.c
@@ -906,7 +906,6 @@ static struct scsi_host_template driver_template = {
         .unchecked_isa_dma          = 0,
         .emulated                   = 0,
         .use_clustering             = ENABLE_CLUSTERING,
-        .use_sg_chaining            = ENABLE_SG_CHAINING,
         .proc_name                  = driver_name,
         .shost_attrs                = hptiop_attrs,
         .this_id                    = -1,
diff --git a/drivers/scsi/ibmmca.c b/drivers/scsi/ibmmca.c
index db004a450732..4d15a62914e9 100644
--- a/drivers/scsi/ibmmca.c
+++ b/drivers/scsi/ibmmca.c
@@ -1501,7 +1501,6 @@ static struct scsi_host_template ibmmca_driver_template = {
           .sg_tablesize   = 16,
           .cmd_per_lun    = 1,
           .use_clustering = ENABLE_CLUSTERING,
-          .use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 static int ibmmca_probe(struct device *dev)
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 30819012898f..78d46a900bb5 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -1600,7 +1600,6 @@ static struct scsi_host_template driver_template = {
         .this_id = -1,
         .sg_tablesize = SG_ALL,
         .use_clustering = ENABLE_CLUSTERING,
-        .use_sg_chaining = ENABLE_SG_CHAINING,
         .shost_attrs = ibmvscsi_attrs,
 };
 
diff --git a/drivers/scsi/initio.c b/drivers/scsi/initio.c
index a10a5c74b48d..0cc8868ea35d 100644
--- a/drivers/scsi/initio.c
+++ b/drivers/scsi/initio.c
@@ -2833,7 +2833,6 @@ static struct scsi_host_template initio_template = {
         .sg_tablesize           = SG_ALL,
         .cmd_per_lun            = 1,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 static int initio_probe_one(struct pci_dev *pdev,
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index e5be5fd4ef58..b6f99dfbb038 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1933,7 +1933,6 @@ static struct scsi_host_template iscsi_sht = {
         .eh_device_reset_handler= iscsi_eh_device_reset,
         .eh_host_reset_handler  = iscsi_eh_host_reset,
         .use_clustering         = DISABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .slave_configure        = iscsi_tcp_slave_configure,
         .proc_name              = "iscsi_tcp",
         .this_id                = -1,
diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 6483c62730b3..fc5c3a42b05a 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -1459,7 +1459,6 @@ struct scsi_host_template lpfc_template = {
         .scan_finished          = lpfc_scan_finished,
         .this_id                = -1,
         .sg_tablesize           = LPFC_DEFAULT_SG_SEG_CNT,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .cmd_per_lun            = LPFC_CMD_PER_LUN,
         .use_clustering         = ENABLE_CLUSTERING,
         .shost_attrs            = lpfc_hba_attrs,
@@ -1482,7 +1481,6 @@ struct scsi_host_template lpfc_vport_template = {
         .sg_tablesize           = LPFC_DEFAULT_SG_SEG_CNT,
         .cmd_per_lun            = LPFC_CMD_PER_LUN,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .shost_attrs            = lpfc_vport_attrs,
         .max_sectors            = 0xFFFF,
 };
diff --git a/drivers/scsi/mac53c94.c b/drivers/scsi/mac53c94.c
index a035001f4438..b12ad7c7c673 100644
--- a/drivers/scsi/mac53c94.c
+++ b/drivers/scsi/mac53c94.c
@@ -402,7 +402,6 @@ static struct scsi_host_template mac53c94_template = {
         .sg_tablesize   = SG_ALL,
         .cmd_per_lun    = 1,
         .use_clustering = DISABLE_CLUSTERING,
-        .use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 static int mac53c94_probe(struct macio_dev *mdev, const struct of_device_id *match)
diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index 765c24d2bc38..4d59ae8491a4 100644
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -4490,7 +4490,6 @@ static struct scsi_host_template megaraid_template = {
         .sg_tablesize                   = MAX_SGLIST,
         .cmd_per_lun                    = DEF_CMD_PER_LUN,
         .use_clustering                 = ENABLE_CLUSTERING,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
         .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 24e32e446e76..6db77c00e3ee 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.c
+++ b/drivers/scsi/megaraid/megaraid_mbox.c
@@ -361,7 +361,6 @@ static struct scsi_host_template megaraid_template_g = {
         .eh_host_reset_handler          = megaraid_reset_handler,
         .change_queue_depth             = megaraid_change_queue_depth,
         .use_clustering                 = ENABLE_CLUSTERING,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
         .sdev_attrs                     = megaraid_sdev_attrs,
         .shost_attrs                    = megaraid_shost_attrs,
 };
diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index d7ec921865c4..672c759ac24d 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -1192,7 +1192,6 @@ static struct scsi_host_template megasas_template = {
         .eh_timed_out = megasas_reset_timer,
         .bios_param = megasas_bios_param,
         .use_clustering = ENABLE_CLUSTERING,
-        .use_sg_chaining = ENABLE_SG_CHAINING,
 };
 
 /**
diff --git a/drivers/scsi/mesh.c b/drivers/scsi/mesh.c
index 7470ff39ab22..651d09b08f2a 100644
--- a/drivers/scsi/mesh.c
+++ b/drivers/scsi/mesh.c
@@ -1843,7 +1843,6 @@ static struct scsi_host_template mesh_template = {
         .sg_tablesize                   = SG_ALL,
         .cmd_per_lun                    = 2,
         .use_clustering                 = DISABLE_CLUSTERING,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
 };
 
 static int mesh_probe(struct macio_dev *mdev, const struct of_device_id *match)
diff --git a/drivers/scsi/nsp32.c b/drivers/scsi/nsp32.c
index 28161dc95e0d..7fed35372150 100644
--- a/drivers/scsi/nsp32.c
+++ b/drivers/scsi/nsp32.c
@@ -281,7 +281,6 @@ static struct scsi_host_template nsp32_template = {
         .cmd_per_lun                    = 1,
         .this_id                        = NSP32_HOST_SCSIID,
         .use_clustering                 = DISABLE_CLUSTERING,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
         .eh_abort_handler               = nsp32_eh_abort,
         .eh_bus_reset_handler           = nsp32_eh_bus_reset,
         .eh_host_reset_handler          = nsp32_eh_host_reset,
diff --git a/drivers/scsi/pcmcia/sym53c500_cs.c b/drivers/scsi/pcmcia/sym53c500_cs.c
index 969b9387a0c3..3454a5714749 100644
--- a/drivers/scsi/pcmcia/sym53c500_cs.c
+++ b/drivers/scsi/pcmcia/sym53c500_cs.c
@@ -692,7 +692,6 @@ static struct scsi_host_template sym53c500_driver_template = {
      .sg_tablesize              = 32,
      .cmd_per_lun               = 1,
      .use_clustering            = ENABLE_CLUSTERING,
-     .use_sg_chaining           = ENABLE_SG_CHAINING,
      .shost_attrs               = SYM53C500_shost_attrs
 };
 
diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c
index c94906abfee3..68c0d09ffe78 100644
--- a/drivers/scsi/qla1280.c
+++ b/drivers/scsi/qla1280.c
@@ -4204,7 +4204,6 @@ static struct scsi_host_template qla1280_driver_template = {
         .sg_tablesize           = SG_ALL,
         .cmd_per_lun            = 1,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index aba1e6d48066..3954ed2d7b51 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -131,7 +131,6 @@ static struct scsi_host_template qla2x00_driver_template = {
         .this_id                = -1,
         .cmd_per_lun            = 3,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .sg_tablesize           = SG_ALL,
 
         /*
@@ -163,7 +162,6 @@ struct scsi_host_template qla24xx_driver_template = {
         .this_id                = -1,
         .cmd_per_lun            = 3,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .sg_tablesize           = SG_ALL,
 
         .max_sectors            = 0xFFFF,
diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index d3f86646cb08..2e2b9fedffcc 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -94,7 +94,6 @@ static struct scsi_host_template qla4xxx_driver_template = {
         .this_id                = -1,
         .cmd_per_lun            = 3,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .sg_tablesize           = SG_ALL,
 
         .max_sectors            = 0xFFFF,
diff --git a/drivers/scsi/qlogicfas.c b/drivers/scsi/qlogicfas.c
index 1769f965eedf..1e874f1fb5c6 100644
--- a/drivers/scsi/qlogicfas.c
+++ b/drivers/scsi/qlogicfas.c
@@ -197,7 +197,6 @@ static struct scsi_host_template qlogicfas_driver_template = {
         .sg_tablesize           = SG_ALL,
         .cmd_per_lun            = 1,
         .use_clustering         = DISABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 static __init int qlogicfas_init(void)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 4560713ecb14..e1c7eebfe907 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/bio.h>
+#include <linux/bitops.h>
 #include <linux/blkdev.h>
 #include <linux/completion.h>
 #include <linux/kernel.h>
@@ -34,13 +35,6 @@
 #define SG_MEMPOOL_NR           ARRAY_SIZE(scsi_sg_pools)
 #define SG_MEMPOOL_SIZE         2
 
-/*
- * The maximum number of SG segments that we will put inside a scatterlist
- * (unless chaining is used). Should ideally fit inside a single page, to
- * avoid a higher order allocation.
- */
-#define SCSI_MAX_SG_SEGMENTS    128
-
 struct scsi_host_sg_pool {
         size_t          size;
         char            *name;
@@ -48,19 +42,26 @@ struct scsi_host_sg_pool {
         mempool_t       *pool;
 };
 
-#define SP(x) { x, "sgpool-" #x }
+#define SP(x) { x, "sgpool-" __stringify(x) }
+#if (SCSI_MAX_SG_SEGMENTS < 32)
+#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
+#endif
 static struct scsi_host_sg_pool scsi_sg_pools[] = {
         SP(8),
         SP(16),
-#if (SCSI_MAX_SG_SEGMENTS > 16)
-        SP(32),
 #if (SCSI_MAX_SG_SEGMENTS > 32)
-        SP(64),
+        SP(32),
 #if (SCSI_MAX_SG_SEGMENTS > 64)
+        SP(64),
+#if (SCSI_MAX_SG_SEGMENTS > 128)
         SP(128),
+#if (SCSI_MAX_SG_SEGMENTS > 256)
+#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
 #endif
 #endif
 #endif
+#endif
+        SP(SCSI_MAX_SG_SEGMENTS)
 };
 #undef SP
 
@@ -692,42 +693,16 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
         return NULL;
 }
 
-/*
- * Like SCSI_MAX_SG_SEGMENTS, but for archs that have sg chaining. This limit
- * is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
- */
-#define SCSI_MAX_SG_CHAIN_SEGMENTS      2048
-
 static inline unsigned int scsi_sgtable_index(unsigned short nents)
 {
         unsigned int index;
 
-        switch (nents) {
-        case 1 ... 8:
+        BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
+
+        if (nents <= 8)
                 index = 0;
-                break;
-        case 9 ... 16:
-                index = 1;
-                break;
-#if (SCSI_MAX_SG_SEGMENTS > 16)
-        case 17 ... 32:
-                index = 2;
-                break;
-#if (SCSI_MAX_SG_SEGMENTS > 32)
-        case 33 ... 64:
-                index = 3;
-                break;
-#if (SCSI_MAX_SG_SEGMENTS > 64)
-        case 65 ... 128:
-                index = 4;
-                break;
-#endif
-#endif
-#endif
-        default:
-                printk(KERN_ERR "scsi: bad segment count=%d\n", nents);
-                BUG();
-        }
+        else
+                index = get_count_order(nents) - 3;
 
         return index;
 }
@@ -1603,20 +1578,7 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
          * this limit is imposed by hardware restrictions
          */
         blk_queue_max_hw_segments(q, shost->sg_tablesize);
-
-        /*
-         * In the future, sg chaining support will be mandatory and this
-         * ifdef can then go away. Right now we don't have all archs
-         * converted, so better keep it safe.
-         */
-#ifdef ARCH_HAS_SG_CHAIN
-        if (shost->use_sg_chaining)
-                blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
-        else
-                blk_queue_max_phys_segments(q, SCSI_MAX_SG_SEGMENTS);
-#else
-        blk_queue_max_phys_segments(q, SCSI_MAX_SG_SEGMENTS);
-#endif
+        blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
 
         blk_queue_max_sectors(q, shost->max_sectors);
         blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index e3fab3a6aed7..72f6d8015358 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -1123,7 +1123,6 @@ static struct scsi_host_template driver_template = {
         .this_id                        = -1,
         .sg_tablesize                   = ST_MAX_SG,
         .cmd_per_lun                    = ST_CMD_PER_LUN,
-        .use_sg_chaining                = ENABLE_SG_CHAINING,
 };
 
 static int stex_set_dma_mask(struct pci_dev * pdev)
diff --git a/drivers/scsi/sym53c416.c b/drivers/scsi/sym53c416.c
index 1f6fd1680335..6325901e5093 100644
--- a/drivers/scsi/sym53c416.c
+++ b/drivers/scsi/sym53c416.c
@@ -840,6 +840,5 @@ static struct scsi_host_template driver_template = {
         .cmd_per_lun =          1,
         .unchecked_isa_dma =    1,
         .use_clustering =       ENABLE_CLUSTERING,
-        .use_sg_chaining =      ENABLE_SG_CHAINING,
 };
 #include "scsi_module.c"
diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index e939f3813233..d39107b7669b 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -1681,7 +1681,6 @@ static struct scsi_host_template sym2_template = {
         .eh_host_reset_handler  = sym53c8xx_eh_host_reset_handler,
         .this_id                = 7,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
         .max_sectors            = 0xFFFF,
 #ifdef SYM_LINUX_PROC_INFO_SUPPORT
         .proc_info              = sym53c8xx_proc_info,
diff --git a/drivers/scsi/u14-34f.c b/drivers/scsi/u14-34f.c
index 4bc5407f9695..662c00451be4 100644
--- a/drivers/scsi/u14-34f.c
+++ b/drivers/scsi/u14-34f.c
@@ -451,7 +451,6 @@ static struct scsi_host_template driver_template = {
                 .this_id                 = 7,
                 .unchecked_isa_dma       = 1,
                 .use_clustering          = ENABLE_CLUSTERING,
-                .use_sg_chaining         = ENABLE_SG_CHAINING,
                 };
 
 #if !defined(__BIG_ENDIAN_BITFIELD) && !defined(__LITTLE_ENDIAN_BITFIELD)
diff --git a/drivers/scsi/ultrastor.c b/drivers/scsi/ultrastor.c
index 75eca6b22db5..f385dce8dfbe 100644
--- a/drivers/scsi/ultrastor.c
+++ b/drivers/scsi/ultrastor.c
@@ -1204,6 +1204,5 @@ static struct scsi_host_template driver_template = {
         .cmd_per_lun       = ULTRASTOR_MAX_CMDS_PER_LUN,
         .unchecked_isa_dma = 1,
         .use_clustering    = ENABLE_CLUSTERING,
-        .use_sg_chaining   = ENABLE_SG_CHAINING,
 };
 #include "scsi_module.c"
diff --git a/drivers/scsi/wd7000.c b/drivers/scsi/wd7000.c
index b4304ae78527..c975c01b3a02 100644
--- a/drivers/scsi/wd7000.c
+++ b/drivers/scsi/wd7000.c
@@ -1671,7 +1671,6 @@ static struct scsi_host_template driver_template = {
         .cmd_per_lun            = 1,
         .unchecked_isa_dma      = 1,
         .use_clustering         = ENABLE_CLUSTERING,
-        .use_sg_chaining        = ENABLE_SG_CHAINING,
 };
 
 #include "scsi_module.c"