Re: [PATCH] Avoid time_offset overflows

[Andrew Morton]

On Sat, 24 Mar 2007 06:20:45 +0100 (CET) Roman Zippel <zippel@xxxxxxxxxxxxxx> wrote:

> Hi,
> 
> On Fri, 23 Mar 2007, john stultz wrote:
> 
> > @@ -314,8 +314,8 @@ #endif
> >  		    freq_adj += time_freq;
> >  		    freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
> >  		    time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
> > -		    time_offset = (time_offset / NTP_INTERVAL_FREQ)
> > -		    			<< SHIFT_UPDATE;
> > +		    do_div(time_offset, NTP_INTERVAL_FREQ);
> > +		    time_offset <<= SHIFT_UPDATE;
> >  		} /* STA_PLL */
> >  	    } /* txc->modes & ADJ_OFFSET */
> >  	    if (txc->modes & ADJ_TICK)
> 
> This is wrong, time_offset is signed and do_div is unsigned.
> In general I planned to do the same change, but the do_div API could use a 
> little cleanup to provide some clear function for signed/unsigned divide 
> (hopefully with a better name than div_long_long_rem_signed or 
> do_div_llr).
> 

Can we do a minimal thing for 2.6.21, worry about API beautification later?
-
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