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Date: Wed, 15 Feb 2006 17:35:45 -0800
From: Andrew Morton <akpm@osdl.org>
To: Paul Mackerras <paulus@samba.org>
Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, johnstul@us.ibm.com
Subject: Re: [PATCH] Provide an interface for getting the current tick
 length
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Paul Mackerras <paulus@samba.org> wrote:
>
> +u64 current_tick_length(void)
>  +{
>  +	long time_adjust_step, delta_nsec;
>  +
>  +	if ((time_adjust_step = time_adjust) != 0 ) {

<mutters something about coding style>

>  +		/*
>  +		 * Limit the amount of the step to be in the range
>  +		 * -tickadj .. +tickadj
>  +		 */
>  +		time_adjust_step = min(time_adjust_step, (long)tickadj);
>  +		time_adjust_step = max(time_adjust_step, (long)-tickadj);
>  +	}
>  +	delta_nsec = tick_nsec + time_adjust_step * 1000;

Is that going to overflow if sizeof(long) == 4?

>  +	return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
>  +}