| Message ID | 1414667745-7703-5-git-send-email-pang.xunlei@linaro.org |
|---|---|
| State | New |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c index 6948cbd..e84e3a0 100644 --- a/drivers/rtc/rtc-lib.c +++ b/drivers/rtc/rtc-lib.c @@ -45,15 +45,17 @@ int rtc_year_days(unsigned int day, unsigned int month, unsigned int year) } EXPORT_SYMBOL(rtc_year_days); + /* * Convert seconds since 01-01-1970 00:00:00 to Gregorian date. + * Safe version for 2038 safety. */ -void rtc_time_to_tm(unsigned long time, struct rtc_time *tm) +void rtc_time_to_tm64(time64_t time, struct rtc_time *tm) { 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); time -= tm->tm_hour * 3600; - tm->tm_min = time / 60; + tm->tm_min = div_s64(time, 60); tm->tm_sec = time - tm->tm_min * 60; tm->tm_isdst = 0; } +EXPORT_SYMBOL(rtc_time_to_tm64); + +/* TODO: [2038 safety] should be replaced by rtc_time_to_tm64() */ +void rtc_time_to_tm(unsigned long time, struct rtc_time *tm) +{ + time64_t time64; + + time64 = (time64_t)time; + rtc_time_to_tm64(time64, tm); +} EXPORT_SYMBOL(rtc_time_to_tm); /* diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 2a6a9ce..12bacba 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -21,6 +21,7 @@ extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year extern int rtc_valid_tm(struct rtc_time *tm); extern int rtc_tm_to_time64(struct rtc_time *tm, time64_t *time); extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time); +extern void rtc_time_to_tm64(time64_t time, struct rtc_time *tm); extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm); ktime_t rtc_tm_to_ktime(struct rtc_time tm); struct rtc_time rtc_ktime_to_tm(ktime_t kt);
As part of addressing 2038 saftey for in-kernel uses, this patch adds safe rtc_time_to_tm64() using time64_t. After this patch, rtc_time_to_tm() should be replaced by rtc_time_to_tm64() one by one. Eventually, rtc_time_to_tm() will be removed from the kernel when it has no users. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> --- drivers/rtc/rtc-lib.c | 20 ++++++++++++++++---- include/linux/rtc.h | 1 + 2 files changed, 17 insertions(+), 4 deletions(-)