[LTP] [PATCH] runpwtests03: use expr to calculate total_cpus for runpwtests03

[Po-Hsu Lin]

The arithmetic operation (( total_cpus-=1 )) does not work for dash,
which was symbolic linked to /bin/sh on some OS like Ubuntu.

In such case, people will see error like:
  runpwtests03.sh: total_cpus-=1: not found

And this further leads to access for a non-existing file and cause
false-positive result in the end:
  runpwtests03.sh: cannot create
  /sys/devices/system/cpu/cpu8/cpufreq/scaling_governor: Directory nonexistent
  runpwtests03.sh: FAIL: Unable to set governor -- powersave for cpu8
  Power_Management03 2 TFAIL: Changing governors

Use expr instead for fix this issue.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
---
 testcases/kernel/power_management/runpwtests03.sh | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/testcases/kernel/power_management/runpwtests03.sh b/testcases/kernel/power_management/runpwtests03.sh
index 11197937f..3fb85d273 100755
--- a/testcases/kernel/power_management/runpwtests03.sh
+++ b/testcases/kernel/power_management/runpwtests03.sh
@@ -25,8 +25,7 @@ export TST_TOTAL=4
 . pm_include.sh
 
 check_cpufreq_sysfs_files() {
-	total_cpus=$(tst_ncpus)
-	(( total_cpus-=1 ))
+	total_cpus=`expr $(tst_ncpus) - 1`
 	RC=0
 
 	for cpu in $(seq 0 "${total_cpus}" )
@@ -51,8 +50,7 @@ check_cpufreq_sysfs_files() {
 change_govr() {
 	available_govr=$(get_supporting_govr)
 
-	total_cpus=$(tst_ncpus)
-	(( total_cpus-=1 ))
+	total_cpus=`expr $(tst_ncpus) - 1`
 	RC=0
 
 	for cpu in $(seq 0 "${total_cpus}" )
@@ -79,8 +77,7 @@ change_freq() {
 	available_govr=$(get_supporting_govr)
 	RC=0
 
-	total_cpus=$(tst_ncpus)
-	(( total_cpus-=1 ))
+	total_cpus=`expr $(tst_ncpus) - 1`
 
 	if ( echo ${available_govr} | grep -i "userspace" \
 		>/dev/null 2>&1 ); then
-- 
2.17.1