Re: do_div vs sector_t

[Andrew Morton]

Christoph Hellwig <[e-mail]> wrote:
>
> On Fri, Jul 11, 2003 at 11:33:59PM +0100, Matthew Wilcox wrote:
> >                         aic->seek_mean = aic->seek_total + 128;
> >                         do_div(aic->seek_mean, aic->seek_samples);
> >                 }
> > 
> > seek_mean is a sector_t so sometimes it's 64-bit on a 32-bit platform.
> > so we can't avoid calling do_div().
> 
> That's why we have sector_div, never use do_div on a sector_t.

Thing is, the arith in there can overflow with 32-bit sector_t anyway, so
we need 64-bit quantities regardless of the CONFIG_LBD setting.