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

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2019/06/25 18:03, Po-Hsu Lin wrote:
> 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`

Hi,

It's wrong for single variable to use $(), did you mean ${tst_ncpus}?

Best Regards,
Xiao Yang
>   	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