[v3,5/5] selftests/resctrl: Fix resctrl_tests' return code to work with selftest framework

In kselftest framework, if a sub test can not run by some reasons,
the test result should be marked as SKIP rather than FAIL.
Return KSFT_SKIP(4) instead of KSFT_FAIL(1) if resctrl_tests is not run
as root or it is run on a test environment which does not support resctrl.

 - ksft_exit_fail_msg(): returns KSFT_FAIL(1)
 - ksft_exit_skip(): returns KSFT_SKIP(4)

Signed-off-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
---
Some important feedbacks from v1&v2 are addressed as follows:

- It is important to highlight that a skipped test is marked
  as successful to not unnecessarily report a feature failure
  when there actually is a failure in the test environment.
  => I highligted this content in changelog as follows.
     "In kselftest framework, if a test is not run by some reason,
     the test result is marked as SKIP rather than FAIL."

- The subject line can be made more succinct while the details are
  moved to the commit message.
  => I made subject line succinct and moved the details to changelog.

- How changing ksft_exit_fail_msg() to ksft_exit_skip() accomplishes
  the goal of unifying the return code.
  => In changelog, I explained why return code KSFT_SKIP(4) is needed
     in kselftest framework and the return code of each function.

 tools/testing/selftests/resctrl/resctrl_tests.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

On 2/15/22 7:26 PM, Shaopeng Tan wrote:
> In kselftest framework, if a sub test can not run by some reasons,
> the test result should be marked as SKIP rather than FAIL.
> Return KSFT_SKIP(4) instead of KSFT_FAIL(1) if resctrl_tests is not run
> as root or it is run on a test environment which does not support resctrl.
> 
>   - ksft_exit_fail_msg(): returns KSFT_FAIL(1)
>   - ksft_exit_skip(): returns KSFT_SKIP(4)
> 

Thank for making this change to skip.

> Signed-off-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
> ---
> Some important feedbacks from v1&v2 are addressed as follows:
> 
> - It is important to highlight that a skipped test is marked
>    as successful to not unnecessarily report a feature failure
>    when there actually is a failure in the test environment.
>    => I highligted this content in changelog as follows.
>       "In kselftest framework, if a test is not run by some reason,
>       the test result is marked as SKIP rather than FAIL."
> 
> - The subject line can be made more succinct while the details are
>    moved to the commit message.
>    => I made subject line succinct and moved the details to changelog.
> 
> - How changing ksft_exit_fail_msg() to ksft_exit_skip() accomplishes
>    the goal of unifying the return code.
>    => In changelog, I explained why return code KSFT_SKIP(4) is needed
>       in kselftest framework and the return code of each function.
> 
>   tools/testing/selftests/resctrl/resctrl_tests.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
> index 973f09a66e1e..3be0895c492b 100644
> --- a/tools/testing/selftests/resctrl/resctrl_tests.c
> +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
> @@ -205,7 +205,7 @@ int main(int argc, char **argv)
>   	 * 2. We execute perf commands
>   	 */
>   	if (geteuid() != 0)
> -		return ksft_exit_fail_msg("Not running as root, abort testing.\n");
> +		return ksft_exit_skip("Not running as root, abort testing.\n");

Let's update the message to "This test must be run as root. Skipping..."
>   
>   	/* Detect AMD vendor */
>   	detect_amd();
> @@ -235,7 +235,7 @@ int main(int argc, char **argv)
>   	sprintf(bm_type, "fill_buf");
>   
>   	if (!check_resctrlfs_support())
> -		return ksft_exit_fail_msg("resctrl FS does not exist\n");
> +		return ksft_exit_skip("resctrl FS does not exist\n");

Update the message to read -

"resctrl FS doesn not exist. Enable X86_CPU_RESCTRL and PROC_CPU_RESCTRL config options"

>   
>   	filter_dmesg();
>   
> 

With these changes:

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah