linux-kernel - Re: [PATCH v4] time: Fix extra sleeptime injection when suspend fails

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Date:   Tue, 17 Jul 2018 11:49:46 +0530
From:   Mukesh Ojha <mojha@...eaurora.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     john.stultz@...aro.org, linux-kernel@...r.kernel.org,
        gkohli@...eaurora.org, cpandya@...eaurora.org,
        neeraju@...eaurora.org
Subject: Re: [PATCH v4] time: Fix extra sleeptime injection when suspend fails



On 7/17/2018 2:20 AM, Thomas Gleixner wrote:
> On Tue, 17 Jul 2018, Mukesh Ojha wrote:
>> @@ -102,7 +102,7 @@ static int rtc_resume(struct device *dev)
>>   	struct timespec64	sleep_time;
>>   	int err;
>>   
>> -	if (timekeeping_rtc_skipresume())
>> +	if (!timekeeping_rtc_skipresume())
>>   		return 0;
> That does not make any sense at all, really.
>
>>   /* Flag for if there is a persistent clock on this platform */
>>   static bool persistent_clock_exists;
>> @@ -1610,7 +1622,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
>>    */
>>   bool timekeeping_rtc_skipresume(void)
>>   {
>> -	return sleeptime_injected;
>> +	return suspend_timing_needed;
> Just make this !suspend_timing_needed and the function name and its return
> value still makes sense.
>
>> @@ -1701,13 +1714,13 @@ void timekeeping_resume(void)
>>   					      tk->tkr_mono.mask);
>>   		nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
>>   		ts_delta = ns_to_timespec64(nsec);
>> -		sleeptime_injected = true;
>> +		suspend_timing_needed = false;
>>   	} else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
>>   		ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
>> -		sleeptime_injected = true;
>> +		suspend_timing_needed = false;
>>   	}
>>   
>> -	if (sleeptime_injected)
>> +	if (!suspend_timing_needed)
>>   		__timekeeping_inject_sleeptime(tk, &ts_delta);
> This reads odd as well. I'd rather keep a local variable inject_sleeptime
> or such and set that in the code pathes above.
>
>     	if (...) {
> 	   	...
> 		inject_sleeptime = true;
>     	} else if (...) {
> 	   	...
> 		inject_sleeptime = true;
> 	}
>
> 	if (inject_sleeptime) {
> 		suspend_timing_needed = false;
> 		__timekeeping_inject_sleeptime();
> 	}

Will do suggested change and send in v5.

Thanks.
>
> Hmm? Just blindly converting everything results in functional, but
> nonsensical code. Think about what happens when you look at that stuff 6
> month from now...
>
> Thanks,
>
> 	tglx
>