Re: [PATCH 5.14 298/334] time: Handle negative seconds correctly in timespec64_to_ns()

Thomas Gleixner
2021-09-16T22:38:47Z

On Thu, Sep 16 2021 at 22:57, Arnd Bergmann wrote:
> On Thu, Sep 16, 2021 at 6:50 PM OPENSOURCE Lukas Hannen
> <lukas.hannen@opensource.tttech-industrial.com> wrote:
> I did stumble over one small detail:
>
> if (ts->tv_sec <= KTIME_SEC_MIN)
> return KTIME_MIN;
>
> I think this is not entirely correct for the case of tv_sec==KTIME_SEC_MIN
> with a nonzero tv_nsec, as we now round down to the full second. Not sure
> if that's worth changing, as we also round up for any value between
> KTIME_SEC_MAX*NSEC_PER_SEC and KTIME_MAX, or between
> KTIME_MIN and KTIME_SEC_MIN*NSEC_PER_SEC.
> In practice I guess we care very little about the last nanosecond in the corner
> cases.

It's completely irrelevant whether the result is off by one second
related to the 292 years limit.

Thanks,

tglx