Re: [PATCH v2 1/7] timekeeping: introduce __current_kernel_time64

From: John Stultz
Date: Tue Nov 10 2015 - 10:26:10 EST


On Tue, Nov 10, 2015 at 7:10 AM, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Tue, 10 Nov 2015, Arnd Bergmann wrote:
>> On Tuesday 10 November 2015 11:57:49 Stefano Stabellini wrote:
>> > __current_kernel_time64 returns a struct timespec64, without taking the
>> > xtime lock. Mirrors __current_kernel_time/current_kernel_time.
>> >
>>
>> Actually it doesn't mirror __current_kernel_time/current_kernel_time
>>
>> > diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
>> > index ec89d84..b5802bf 100644
>> > --- a/include/linux/timekeeping.h
>> > +++ b/include/linux/timekeeping.h
>> > @@ -19,7 +19,8 @@ extern int do_sys_settimeofday(const struct timespec *tv,
>> > */
>> > unsigned long get_seconds(void);
>> > struct timespec64 current_kernel_time64(void);
>> > -/* does not take xtime_lock */
>> > +/* do not take xtime_lock */
>> > +struct timespec64 __current_kernel_time64(void);
>> > struct timespec __current_kernel_time(void);
>>
>> Please change __current_kernel_time into a static inline function
>> while you are introducing the new one, to match the patch description ;-)
>
> The implementation is:
>
> struct timekeeper *tk = &tk_core.timekeeper;
>
> return timespec64_to_timespec(tk_xtime(tk));
>
> which cannot be easily made into a static inline, unless we start
> exporting tk_core.

So the timekeeper is passed to the notifier. So you probably want something like

struct timespec64 __current_kernel_time64(struct timekeeper *tk)
{
return timespec64_to_timespec(tk_xtime(tk));
}

Then you can cast the priv pointer in the notifier to a timekeeper and
use it that way?

thanks
-john
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