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

[Thomas Gleixner <tglx@linutronix.de>]

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