[PATCH 1/6] common/scsi_debug: don't slow down I/O

[Christoph Hellwig <hch@lst.de>]

scsi_debug by defaults delays I/O and doesn't support multi-page I/O.
Flipping these defaults speed up each test using scsi_debug by more than
an order of magnitute on my test systems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
 common/scsi_debug | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/common/scsi_debug b/common/scsi_debug
index c3fe7be623fa..af51905dc4ba 100644
--- a/common/scsi_debug
+++ b/common/scsi_debug
@@ -59,9 +59,19 @@ _get_scsi_debug_dev()
 		let physical=physical/2
 		let phys_exp=phys_exp+1
 	done
-	opts="sector_size=$logical physblk_exp=$phys_exp lowest_aligned=$unaligned dev_size_mb=$size $@"
-	echo "scsi_debug options $opts" >> $seqres.full
-	modprobe scsi_debug $opts
+
+	local opts=(
+		"sector_size=$logical"
+		"physblk_exp=$phys_exp"
+		"lowest_aligned=$unaligned"
+		"dev_size_mb=$size"
+		"delay=0"
+		"clustering=1"
+	)
+	opts+=("$@")
+
+	echo "scsi_debug options ${opts[*]}" >> $seqres.full
+	modprobe scsi_debug "${opts[@]}"
 	[ $? -eq 0 ] || _fail "scsi_debug modprobe failed"
 	$UDEV_SETTLE_PROG
 	device=`grep -wl scsi_debug /sys/block/sd*/device/model | awk -F / '{print $4}'`
-- 
2.53.0