throtl: support test with both null_blk and scsi_debug in a single run

The previous commit introduced the global variable throtl_blkdev_type to
specify the type of block device for the throtl group. However, users
need to run tests twice modifying the variable's value each time to test
against both device types null_blk and scsi_debug. This workflow is
cumbersome.

To run the throtl group for both null_blk and scsi_debug in a single
run, introduce the global variable THROTL_BLKDEV_TYPES instead of
throtl_blkdev_type. When THROTL_BLKDEV_TYPES is set to 'nullb sdebug',
the blktests framework executes each test case in the throtl group for
both null_blk and scsi_debug sequentially. For this purpose, introduce
the helper function _set_throtl_blkdev_type() and call it in
set_conditions() hooks of the test cases.

Each of the two command lines below runs the throtl group with both
null_blk and scsi_debug. Please note that the default value of
THROTL_BLKDEV_TYPES is 'nullb sdebug'.

  $ sudo bash -c "./check throtl/"
  $ sudo bash -c "THROTL_BLKDEV_TYPES='nullb sdebug' ./check throtl/"

Each of the command lines below runs the throtl group only for null_blk
or scsi_debug, respectively.

  $ sudo bash -c "THROTL_BLKDEV_TYPES='nullb' ./check throtl/"
  $ sudo bash -c "THROTL_BLKDEV_TYPES='sdebug' ./check throtl/"

Reviewed-by: Chaitanya Kulkarni <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>

Author: kawasaki

Documentation/running-tests.md

@@ -167,6 +167,23 @@ USE_RXE=1 ./check srp/
 'USE_RXE' had the old name 'use_rxe'. The old name is still usable but not
 recommended.
 
+### Blk-throttle tests
+
+The blk-throttle tests has one environment variable below:
+
+- THROTL_BLKDEV_TYPES: 'nullb' 'sdebug'
+  Set up test target block device based on this environment variable value. To
+  test with null_blk, set 'nullb'. To test with scsi_debug, set 'sdebug'. To
+  test with both, set 'nullb sdebug'. Default value is 'nullb sdebug'.
+
+```sh
+To run with scsi_debug:
+THROTL_BLKDEV_TYPES="sdebug" ./check throtl/
+
+To run with both null_blk and scsi_debug:
+THROTL_BLKDEV_TYPES="nullb sdebug" ./check throtl/
+```
+
 ### Normal user
 
 To run test cases which require normal user privilege, prepare a user and

tests/throtl/001

@@ -9,6 +9,10 @@
 DESCRIPTION="basic functionality"
 QUICK=1
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test() {
 	echo "Running ${TEST_NAME}"
 

tests/throtl/002

@@ -10,6 +10,10 @@
 DESCRIPTION="iops limit over IO split"
 QUICK=1
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test() {
 	echo "Running ${TEST_NAME}"
 

tests/throtl/003

@@ -10,6 +10,10 @@
 DESCRIPTION="bps limit over IO split"
 QUICK=1
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test() {
 	echo "Running ${TEST_NAME}"
 

tests/throtl/004

@@ -11,6 +11,10 @@
 DESCRIPTION="delete disk while IO is throttled"
 QUICK=1
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test() {
 	echo "Running ${TEST_NAME}"
 

tests/throtl/005

@@ -10,6 +10,10 @@
 DESCRIPTION="change config with throttled IO"
 QUICK=1
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test() {
 	echo "Running ${TEST_NAME}"
 

tests/throtl/006

@@ -15,6 +15,10 @@ requires() {
 	_have_driver ext4
 }
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test_meta_io() {
 	local path="$1"
 	local start_time

tests/throtl/007

@@ -11,6 +11,10 @@
 DESCRIPTION="bps limit with iops limit over io split"
 QUICK=1
 
+set_conditions() {
+	_set_throtl_blkdev_type "$@"
+}
+
 test() {
 	echo "Running ${TEST_NAME}"
 

tests/throtl/rc

@@ -10,6 +10,7 @@
 . common/cgroup
 
 THROTL_DIR=$(echo "$TEST_NAME" | tr '/' '_')
+THROTL_BLKDEV_TYPES=${THROTL_BLKDEV_TYPES:-"nullb sdebug"}
 throtl_blkdev_type=${throtl_blkdev_type:-"nullb"}
 THROTL_NULL_DEV=dev_nullb
 declare THROTL_DEV
@@ -25,6 +26,21 @@ group_requires() {
 	_have_program bc
 }
 
+_set_throtl_blkdev_type() {
+	local index=$1
+	local -a types
+
+	read -r -a types <<< "${THROTL_BLKDEV_TYPES[@]}"
+
+	if [[ -z $index ]]; then
+		echo ${#types[@]}
+		return
+	fi
+
+	throtl_blkdev_type=${types[index]}
+	COND_DESC="${throtl_blkdev_type}"
+}
+
 # Prepare null_blk or scsi_debug device to test, based on throtl_blkdev_type.
 _configure_throtl_blkdev() {
 	local sector_size=0 memory_backed=0