scsi_debug: Increase the reported optimal transfer length

The OPTIMAL TRANSFER LENGTH reported by scsi_debug is 64 blocks which
translates to 32KB with the default logical block size. That's much
lower than what real storage devices typically report (256KB to 1MB).

Bump the optimal transfer length to 1024 blocks.
Acked-by: NDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_debug.c

@@ -129,7 +129,7 @@ static const char *scsi_debug_version_date = "20141022";
 #define DEF_NO_LUN_0   0
 #define DEF_NUM_PARTS   0
 #define DEF_OPTS   0
-#define DEF_OPT_BLKS 64
+#define DEF_OPT_BLKS 1024
 #define DEF_PHYSBLK_EXP 0
 #define DEF_PTYPE   0
 #define DEF_REMOVABLE false
@@ -4139,7 +4139,7 @@ MODULE_PARM_DESC(no_lun_0, "no LU number 0 (def=0 -> have lun 0)");
 MODULE_PARM_DESC(no_uld, "stop ULD (e.g. sd driver) attaching (def=0))");
 MODULE_PARM_DESC(num_parts, "number of partitions(def=0)");
 MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)");
-MODULE_PARM_DESC(opt_blks, "optimal transfer length in block (def=64)");
+MODULE_PARM_DESC(opt_blks, "optimal transfer length in blocks (def=1024)");
 MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)");
 MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)");
 MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])");