On Tue, Aug 15, 2023 at 8:56 AM Andre Przywara <andre.przywara@xxxxxxx> wrote:
>
> As cachestat is a new syscall, it won't be available on older kernels,
> for instance those running on a build machine. In this case, a run
> reports all tests as "not ok" at the moment.
Interesting - I was under the assumption that if you backported the
selftests for cachestat, you would also backport the syscall's implementation
and wiring.
But yeah, I guess if you build with !CONFIG_CACHESTAT_SYSCALL,
these tests would fail.
>
> Test for the cachestat syscall availability first, before doing further
> tests, and bail out early with a TAP SKIP comment.
>
> This also uses the opportunity to add the proper TAP headers, and add
> one check for the syscall error handling (illegal file descriptor).
Thanks for the addition!
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
> .../selftests/cachestat/test_cachestat.c | 22 ++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/cachestat/test_cachestat.c b/tools/testing/selftests/cachestat/test_cachestat.c
> index a5a4ac8dcb76c..77620e7ecf562 100644
> --- a/tools/testing/selftests/cachestat/test_cachestat.c
> +++ b/tools/testing/selftests/cachestat/test_cachestat.c
> @@ -15,6 +15,8 @@
>
> #include "../kselftest.h"
>
> +#define NR_TESTS 8
> +
> static const char * const dev_files[] = {
> "/dev/zero", "/dev/null", "/dev/urandom",
> "/proc/version", "/proc"
> @@ -235,7 +237,25 @@ bool test_cachestat_shmem(void)
>
> int main(void)
> {
> - int ret = 0;
> + int ret;
> +
> + ksft_print_header();
> +
> + ret = syscall(__NR_cachestat, -1, NULL, NULL, 0);
> + if (ret == -1 && errno == ENOSYS) {
nit: if (ret && errno == ENOSYS) sounds cleaner, but up to you.
> + printf("1..0 # Skipped: cachestat syscall not available\n");
nit: perhaps ksft_print_msg()?
> + return KSFT_SKIP;
> + }
> +
> + ksft_set_plan(NR_TESTS);
> +
> + if (ret == -1 && errno == EBADF) {
> + ksft_test_result_pass("bad file descriptor recognized\n");
> + ret = 0;
> + } else {
> + ksft_test_result_fail("bad file descriptor ignored\n");
> + ret = 1;
> + }
Nice!
>
> for (int i = 0; i < 5; i++) {
> const char *dev_filename = dev_files[i];
> --
> 2.25.1
>
Nitpicking aside:
Acked-by: Nhat Pham <nphamcs@xxxxxxxxx>
