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

[Xiao Yang]

Hi,

Sorry, I missed the fact that tst_ncpus is executable binary.

It's good to me.

Reviewed-by: Xiao Yang <ice_yangxiao@163.com>

BTW: if you don't want to depend expr command, we can fix it by using 
total_cpus=$((total_cpus - 1)) instead.

Best Regards,
Xiao Yang

On 06/26/2019 12:13 AM, Po-Hsu Lin wrote:
> Hello!
>
> The $() here is for the tst_ncpus executable, which will return the
> total cpu number.
>
> Thanks
> PHLin
>
> On Tue, Jun 25, 2019 at 6:59 PM Xiao Yang <yangx.jy@cn.fujitsu.com> wrote:
>> On 2019/06/25 18:03, Po-Hsu Lin wrote:
>>> The arithmetic operation (( total_cpus-=1 )) does not work for dash,
>>> which was symbolic linked to /bin/sh on some OS like Ubuntu.
>>>
>>> In such case, people will see error like:
>>>     runpwtests03.sh: total_cpus-=1: not found
>>>
>>> And this further leads to access for a non-existing file and cause
>>> false-positive result in the end:
>>>     runpwtests03.sh: cannot create
>>>     /sys/devices/system/cpu/cpu8/cpufreq/scaling_governor: Directory nonexistent
>>>     runpwtests03.sh: FAIL: Unable to set governor -- powersave for cpu8
>>>     Power_Management03 2 TFAIL: Changing governors
>>>
>>> Use expr instead for fix this issue.
>>>
>>> Signed-off-by: Po-Hsu Lin<po-hsu.lin@canonical.com>
>>> ---
>>>    testcases/kernel/power_management/runpwtests03.sh | 9 +++------
>>>    1 file changed, 3 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/testcases/kernel/power_management/runpwtests03.sh b/testcases/kernel/power_management/runpwtests03.sh
>>> index 11197937f..3fb85d273 100755
>>> --- a/testcases/kernel/power_management/runpwtests03.sh
>>> +++ b/testcases/kernel/power_management/runpwtests03.sh
>>> @@ -25,8 +25,7 @@ export TST_TOTAL=4
>>>    . pm_include.sh
>>>
>>>    check_cpufreq_sysfs_files() {
>>> -     total_cpus=$(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
>>
>>