| Message ID | 20211110180359.2338349-1-anders.roxell@linaro.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [PATCHv2] selftests: timens: exec: use 'labs()' over 'abs()' | expand |
On Wed, Nov 10, 2021 at 10:04 AM Anders Roxell <anders.roxell@linaro.org> wrote: > > When building selftests/timens with clang, the compiler warn about the > function abs() see below: > > exec.c:33:8: error: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value] > if (abs(tst.tv_sec - now.tv_sec) > 5) > ^ > exec.c:33:8: note: use function 'labs' instead > if (abs(tst.tv_sec - now.tv_sec) > 5) > ^~~ > labs > > Rework to store the time difference in a 'long long' and pass that to > llabs(), since the variable can be an 'int', 'long' or 'long long' > depending on the architecture and C library. > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Thanks for the patch! Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > tools/testing/selftests/timens/exec.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/timens/exec.c b/tools/testing/selftests/timens/exec.c > index e40dc5be2f66..04439e6ac8a2 100644 > --- a/tools/testing/selftests/timens/exec.c > +++ b/tools/testing/selftests/timens/exec.c > @@ -21,6 +21,7 @@ > int main(int argc, char *argv[]) > { > struct timespec now, tst; > + long long timediff; > int status, i; > pid_t pid; > > @@ -30,7 +31,8 @@ int main(int argc, char *argv[]) > > for (i = 0; i < 2; i++) { > _gettime(CLOCK_MONOTONIC, &tst, i); > - if (abs(tst.tv_sec - now.tv_sec) > 5) > + timediff = tst.tv_sec - now.tv_sec; > + if (llabs(timediff) > 5) > return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec); > } > return 0; > @@ -50,7 +52,8 @@ int main(int argc, char *argv[]) > > for (i = 0; i < 2; i++) { > _gettime(CLOCK_MONOTONIC, &tst, i); > - if (abs(tst.tv_sec - now.tv_sec) > 5) > + timediff = tst.tv_sec - now.tv_sec; > + if (llabs(timediff) > 5) > return pr_fail("%ld %ld\n", > now.tv_sec, tst.tv_sec); > } > @@ -70,7 +73,8 @@ int main(int argc, char *argv[]) > /* Check that a child process is in the new timens. */ > for (i = 0; i < 2; i++) { > _gettime(CLOCK_MONOTONIC, &tst, i); > - if (abs(tst.tv_sec - now.tv_sec - OFFSET) > 5) > + timediff = tst.tv_sec - now.tv_sec - OFFSET; > + if (llabs(timediff) > 5) > return pr_fail("%ld %ld\n", > now.tv_sec + OFFSET, tst.tv_sec); > } > -- > 2.33.0 >
On Wed, Nov 10, 2021 at 12:09 PM Nick Desaulniers <ndesaulniers@google.com> wrote: > > On Wed, Nov 10, 2021 at 10:04 AM Anders Roxell <anders.roxell@linaro.org> wrote: > > > > When building selftests/timens with clang, the compiler warn about the > > function abs() see below: > > > > exec.c:33:8: error: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value] > > if (abs(tst.tv_sec - now.tv_sec) > 5) > > ^ > > exec.c:33:8: note: use function 'labs' instead > > if (abs(tst.tv_sec - now.tv_sec) > 5) > > ^~~ > > labs > > > > Rework to store the time difference in a 'long long' and pass that to > > llabs(), since the variable can be an 'int', 'long' or 'long long' > > depending on the architecture and C library. > > > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > > Signed-off-by: Anders Roxell <anders.roxell@linaro.org> > > Thanks for the patch! > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> ah, gmail doesn't do a great job at showing the subject when a v2 is sent in-reply-to. Should the oneline mention llabs rather than labs now? > > > --- > > tools/testing/selftests/timens/exec.c | 10 +++++++--- > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/tools/testing/selftests/timens/exec.c b/tools/testing/selftests/timens/exec.c > > index e40dc5be2f66..04439e6ac8a2 100644 > > --- a/tools/testing/selftests/timens/exec.c > > +++ b/tools/testing/selftests/timens/exec.c > > @@ -21,6 +21,7 @@ > > int main(int argc, char *argv[]) > > { > > struct timespec now, tst; > > + long long timediff; > > int status, i; > > pid_t pid; > > > > @@ -30,7 +31,8 @@ int main(int argc, char *argv[]) > > > > for (i = 0; i < 2; i++) { > > _gettime(CLOCK_MONOTONIC, &tst, i); > > - if (abs(tst.tv_sec - now.tv_sec) > 5) > > + timediff = tst.tv_sec - now.tv_sec; > > + if (llabs(timediff) > 5) > > return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec); > > } > > return 0; > > @@ -50,7 +52,8 @@ int main(int argc, char *argv[]) > > > > for (i = 0; i < 2; i++) { > > _gettime(CLOCK_MONOTONIC, &tst, i); > > - if (abs(tst.tv_sec - now.tv_sec) > 5) > > + timediff = tst.tv_sec - now.tv_sec; > > + if (llabs(timediff) > 5) > > return pr_fail("%ld %ld\n", > > now.tv_sec, tst.tv_sec); > > } > > @@ -70,7 +73,8 @@ int main(int argc, char *argv[]) > > /* Check that a child process is in the new timens. */ > > for (i = 0; i < 2; i++) { > > _gettime(CLOCK_MONOTONIC, &tst, i); > > - if (abs(tst.tv_sec - now.tv_sec - OFFSET) > 5) > > + timediff = tst.tv_sec - now.tv_sec - OFFSET; > > + if (llabs(timediff) > 5) > > return pr_fail("%ld %ld\n", > > now.tv_sec + OFFSET, tst.tv_sec); > > } > > -- > > 2.33.0 > > > > > -- > Thanks, > ~Nick Desaulniers
On Wed, 10 Nov 2021 at 21:11, Nick Desaulniers <ndesaulniers@google.com> wrote: > > On Wed, Nov 10, 2021 at 12:09 PM Nick Desaulniers > <ndesaulniers@google.com> wrote: > > > > On Wed, Nov 10, 2021 at 10:04 AM Anders Roxell <anders.roxell@linaro.org> wrote: > > > > > > When building selftests/timens with clang, the compiler warn about the > > > function abs() see below: > > > > > > exec.c:33:8: error: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value] > > > if (abs(tst.tv_sec - now.tv_sec) > 5) > > > ^ > > > exec.c:33:8: note: use function 'labs' instead > > > if (abs(tst.tv_sec - now.tv_sec) > 5) > > > ^~~ > > > labs > > > > > > Rework to store the time difference in a 'long long' and pass that to > > > llabs(), since the variable can be an 'int', 'long' or 'long long' > > > depending on the architecture and C library. > > > > > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > > > Signed-off-by: Anders Roxell <anders.roxell@linaro.org> > > > > Thanks for the patch! > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > ah, gmail doesn't do a great job at showing the subject when a v2 is > sent in-reply-to. oh right, sorry. > Should the oneline mention llabs rather than labs > now? You are correct, can this be changed when the patch gets applied or should I send a v3? Cheers, Anders
diff --git a/tools/testing/selftests/timens/exec.c b/tools/testing/selftests/timens/exec.c index e40dc5be2f66..04439e6ac8a2 100644 --- a/tools/testing/selftests/timens/exec.c +++ b/tools/testing/selftests/timens/exec.c @@ -21,6 +21,7 @@ int main(int argc, char *argv[]) { struct timespec now, tst; + long long timediff; int status, i; pid_t pid; @@ -30,7 +31,8 @@ int main(int argc, char *argv[]) for (i = 0; i < 2; i++) { _gettime(CLOCK_MONOTONIC, &tst, i); - if (abs(tst.tv_sec - now.tv_sec) > 5) + timediff = tst.tv_sec - now.tv_sec; + if (llabs(timediff) > 5) return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec); } return 0; @@ -50,7 +52,8 @@ int main(int argc, char *argv[]) for (i = 0; i < 2; i++) { _gettime(CLOCK_MONOTONIC, &tst, i); - if (abs(tst.tv_sec - now.tv_sec) > 5) + timediff = tst.tv_sec - now.tv_sec; + if (llabs(timediff) > 5) return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec); } @@ -70,7 +73,8 @@ int main(int argc, char *argv[]) /* Check that a child process is in the new timens. */ for (i = 0; i < 2; i++) { _gettime(CLOCK_MONOTONIC, &tst, i); - if (abs(tst.tv_sec - now.tv_sec - OFFSET) > 5) + timediff = tst.tv_sec - now.tv_sec - OFFSET; + if (llabs(timediff) > 5) return pr_fail("%ld %ld\n", now.tv_sec + OFFSET, tst.tv_sec); }
When building selftests/timens with clang, the compiler warn about the function abs() see below: exec.c:33:8: error: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value] if (abs(tst.tv_sec - now.tv_sec) > 5) ^ exec.c:33:8: note: use function 'labs' instead if (abs(tst.tv_sec - now.tv_sec) > 5) ^~~ labs Rework to store the time difference in a 'long long' and pass that to llabs(), since the variable can be an 'int', 'long' or 'long long' depending on the architecture and C library. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> --- tools/testing/selftests/timens/exec.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)