Messages in this thread | | | Date | Thu, 30 Oct 2014 15:07:00 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [RFC PATCH v2 04/11] time: Add rtc_time_to_tm64() safe version(using time64_t) |
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On Thu, 30 Oct 2014, pang.xunlei wrote:
As you can guess already: $subject sucks.
> + > /* > * Convert seconds since 01-01-1970 00:00:00 to Gregorian date. > + * Safe version for 2038 safety.
See previous replies.
> */ > -void rtc_time_to_tm(unsigned long time, struct rtc_time *tm) > +void rtc_time_to_tm64(time64_t time, struct rtc_time *tm)
What's tm64?
This function is converting time64 to rtc_time. So the proper function name is: rtc_time64_to_tm
Can you see the difference?
> { > unsigned int month, year; > int days; > > - days = time / 86400; > + days = div_s64(time, 86400); > time -= (unsigned int) days * 86400; > > /* day of the week, 1970-01-01 was a Thursday */ > @@ -81,13 +83,23 @@ void rtc_time_to_tm(unsigned long time, struct rtc_time *tm) > tm->tm_mon = month; > tm->tm_mday = days + 1; > > - tm->tm_hour = time / 3600; > + tm->tm_hour = div_s64(time, 3600);
We already adjusted time to a value which is less than 24 * 3600, i.e. it fits nicely into a long on 32bit. So we can avoid the whole div_s64 business and simply do:
unsigned int month, year; + unsigned long secs; int days;
- days = time / 86400; - time -= (unsigned int) days * 86400; + days = div_s64(time, 86400); + secs = time - (unsigned int) days * 86400;
And change the rest which uses time to:
- tm->tm_hour = time / 3600; + tm->tm_hour = secs / 3600;
Sigh.
tglx
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