Re: [PATCH] Don't test nanoseconds for non-LFS interface in io/tst-stat.c

[Stefan Liebler <stli@linux.ibm.com>]

On 16/03/2021 15:24, Adhemerval Zanella wrote:
> 
> 
> On 16/03/2021 10:56, Stefan Liebler wrote:
>> Both new tests io/tst-stat and io/tst-stat-lfs (_FILE_OFFSET_BITS=64)
>> are comparing the nanosecond fields with the statx result.  Unfortunately
>> e.g. on s390(31bit) those fields are always zero if old KABI with non-LFS
>> support is used.  With _FILE_OFFSET_BITS=64 stat is using statx internally.
> 
> This might also happens for LFS interface if statx is not supported by the
> kernel, since the LFS call will fall back to the use the stat syscall that
> has this issue.
> 
> Maybe it would be better to make it an internal tests and add a flag
> somewhere to just disable it for s390-32. 
> 
gcc is setting the macros __s390x__ and __s390__ on s390x(64bit), but
only __s390__ on s390(31bit). Thus I can detect s390(31bit) at
compile-time via "#if" and disable the nanoseconds checks on s390(31bit)
at all and run it on all other cases. Then I don't need to make the test
an internal test and don't need special flags. If this is okay for you,
I will prepare a further patch (also with a different subject).

Thanks,
Stefan