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

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