Re: [PATCH] power: supply: da9150: use div64_u64() instead of do_div()

[Christophe JAILLET]

Le 11/02/2022 à 21:50, Sebastian Reichel a écrit :
> Hi,
>
> On Wed, Feb 09, 2022 at 12:39:46AM -0800, Qing Wang wrote:
> > From: Wang Qing <wangqing@xxxxxxxx>
> >
> > do_div() does a 64-by-32 division.
> > When the divisor is u64, do_div() truncates it to 32 bits, this means it
> > can test non-zero and be truncated to zero for division.
> >
> > fix do_div.cocci warning:
> > do_div() does a 64-by-32 division, please consider using div64_u64 instead.
> >
> > Signed-off-by: Wang Qing <wangqing@xxxxxxxx>
> > ---
>
> Thanks, queued.

All these patches are broken and should be NACKed, fixed or reverted if 
applied.

See [1].

CJ

[1]: 
https://lore.kernel.org/linux-kernel/19b96972-cee7-937f-21ce-c78982ed2048@xxxxxxxxxx/

> -- Sebastian
>
> >   drivers/power/supply/da9150-fg.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/power/supply/da9150-fg.c b/drivers/power/supply/da9150-fg.c
> > index 6e36782..896491a
> > --- a/drivers/power/supply/da9150-fg.c
> > +++ b/drivers/power/supply/da9150-fg.c
> > @@ -250,7 +250,7 @@ static int da9150_fg_current_avg(struct da9150_fg *fg,
> >   	div = (u64) (sd_gain * shunt_val * 65536ULL);
> >   	do_div(div, 1000000);
> >   	res = (u64) (iavg * 1000000ULL);
> > -	do_div(res, div);
> > +	div64_u64(res, div);
> >   
> >   	val->intval = (int) res;
> >   
> > --
> > 2.7.4