Re: [PATCH 1/2] selftests: timens: use 'llabs()' over 'abs()'

[Shuah Khan]

On 11/5/21 2:26 PM, Nick Desaulniers wrote:
> On Fri, Nov 5, 2021 at 9:31 AM Anders Roxell <anders.roxell@xxxxxxxxxx> wrote:
> > When building selftests/timens with clang, the compiler warn about the
> > function abs() see below:
> >
> > timerfd.c:64:7: error: absolute value function 'abs' given an argument of type 'long long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value]
> >                  if (abs(elapsed - 3600) > 60) {
> >                      ^
> > timerfd.c:64:7: note: use function 'llabs' instead
> >                  if (abs(elapsed - 3600) > 60) {
> >                      ^~~
> >                      llabs
> >
> > The note indicates what to do, Rework to use the function 'llabs()'.
> >
> > Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
>
> Thanks for the patch!
> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>
> > ---
> >   tools/testing/selftests/timens/timer.c   | 2 +-
> >   tools/testing/selftests/timens/timerfd.c | 2 +-
> >   2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/testing/selftests/timens/timer.c b/tools/testing/selftests/timens/timer.c
> > index 5e7f0051bd7b..5b939f59dfa4 100644
> > --- a/tools/testing/selftests/timens/timer.c
> > +++ b/tools/testing/selftests/timens/timer.c
> > @@ -56,7 +56,7 @@ int run_test(int clockid, struct timespec now)
> >                          return pr_perror("timerfd_gettime");
> >
> >                  elapsed = new_value.it_value.tv_sec;
> > -               if (abs(elapsed - 3600) > 60) {
> > +               if (llabs(elapsed - 3600) > 60) {
> >                          ksft_test_result_fail("clockid: %d elapsed: %lld\n",
> >                                                clockid, elapsed);
> >                          return 1;
> > diff --git a/tools/testing/selftests/timens/timerfd.c b/tools/testing/selftests/timens/timerfd.c
> > index 9edd43d6b2c1..a4196bbd6e33 100644
> > --- a/tools/testing/selftests/timens/timerfd.c
> > +++ b/tools/testing/selftests/timens/timerfd.c
> > @@ -61,7 +61,7 @@ int run_test(int clockid, struct timespec now)
> >                          return pr_perror("timerfd_gettime(%d)", clockid);
> >
> >                  elapsed = new_value.it_value.tv_sec;
> > -               if (abs(elapsed - 3600) > 60) {
> > +               if (llabs(elapsed - 3600) > 60) {
> >                          ksft_test_result_fail("clockid: %d elapsed: %lld\n",
> >                                                clockid, elapsed);
> >                          return 1;
> > --
> > 2.33.0

Same comment on llabs() define in stdlib.h made earlier in the context
of timer test changes.

thanks,
-- Shuah