Re: [PATCH RFC 05/12] time: Convert rtc_tm_to_time_unsafe() to rtc_tm_to_time() in rtc_hctosys()

From: Thomas Gleixner
Date: Mon Oct 27 2014 - 18:03:10 EST


On Mon, 27 Oct 2014, pang.xunlei wrote:
> The kernel uses 32-bit signed value(time_t) for seconds since 1970-01-01:00:00:00, so it
> will overflow at 2038-01-19 03:14:08 on 32-bit systems. We call this "2038 safety" issue.

We really know that by now. No need to repeat that for every patch.

> As part of addressing 2038 saftey for in-kernel uses, this patch creates no functional change
> in existing users, and converts rtc_tm_to_time_unsafe() to rtc_tm_to_time() in rtc_hctosys().

Please line break your changelogs properly. That's how it should look
like:

> As part of addressing 2038 saftey for in-kernel uses, this patch
> creates no functional change in existing users, and converts
> rtc_tm_to_time_unsafe() to rtc_tm_to_time() in rtc_hctosys().

Can you spot the difference?

> @@ -26,9 +26,10 @@ static int __init rtc_hctosys(void)
> {
> int err = -ENODEV;
> struct rtc_time tm;
> - struct timespec tv = {
> + struct timespec64 tv = {
> .tv_nsec = NSEC_PER_SEC >> 1,
> };
> + struct timespec ts32;

So this is exactly why I dislike this whole flag day conversion
thing. If you add

rtc_tm_to_time64()
do_settimeofday64()

in the first place, you can convert the whole function in one go
without introducing intermediate variables which then need to be
undone later again.

Thanks,

tglx
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