Hello Shuah, On Mon, Jul 30, 2018 at 05:32:30PM -0600, Shuah Khan wrote: > Hi Rafael, > > On 07/30/2018 10:05 AM, Rafael David Tinoco wrote: > > Makes membarrier_test compatible with older kernels (LTS) by checking if > > the membarrier features exist before running the tests. > > > > Link: https://bugs.linaro.org/show_bug.cgi?id=3771 > > Signed-off-by: Rafael David Tinoco <rafael.tinoco@xxxxxxxxxx> > > Cc: <stable@xxxxxxxxxxxxxxx> #v4.17 > > --- > > .../selftests/membarrier/membarrier_test.c | 69 +++++++++++-------- > > 1 file changed, 41 insertions(+), 28 deletions(-) > > > > diff --git a/tools/testing/selftests/membarrier/membarrier_test.c b/tools/testing/selftests/membarrier/membarrier_test.c > > index 6793f8ecc8e7..b96caa096e2f 100644 > > --- a/tools/testing/selftests/membarrier/membarrier_test.c > > +++ b/tools/testing/selftests/membarrier/membarrier_test.c > > @@ -225,7 +225,14 @@ static int test_membarrier_global_expedited_success(void) > > > > static int test_membarrier(void) > > { > > - int status; > > + int supported, status; > > + > > + supported = sys_membarrier(MEMBARRIER_CMD_QUERY, 0); > > + if (supported < 0) { > > + ksft_test_result_fail( > > + "sys_membarrier() failed to query supported cmds\n"); > > + return supported; > > + } > > > > ksft_exit_skip() is the right interface to use here. If feature isn't supported, > it should exit skip as opposed fail. > Not sure this is the case here. This part was just a positional change. This check is extending an existing logic (for MEMBARRIER_CMD_PRIVATE_ EXPEDITED_SYNC_CORE tests). Calling membarrier with MEMBARRIER_CMD_QUERY will return us MEMBARRIER_CMD_BITMASK, telling us which features are enabled for the running kernel (thus which tests can be executed). The query command was added in v4.3 and should (could ?) be considered a fundament for a working test by now, I suppose, no ? It is used to decide which further tests to run. Not receiving anything back from this call would mean something is broken (since at least MEMBARRIER_CMD_GLOBAL should have always existed as a membarrier feature/command). I think your concern is addressed in the beginning of the test. test_membarrier_query() tests for ENOSYS and calls ksft_exit_skip() if CONFIG_MEMBARRIER is disabled. This part is not about checking if the test can run, but which one can. What do you think ? Tks for reviewing! -- Rafael D. Tinoco -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
