| Message ID | 1644395986-4349-1-git-send-email-wangqing@vivo.com |
|---|---|
| State | New |
| Headers | show |
| Series | power: supply: da9150: use div64_u64() instead of do_div() | expand |
Hi, On Wed, Feb 09, 2022 at 12:39:46AM -0800, Qing Wang wrote: > From: Wang Qing <wangqing@vivo.com> > > 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@vivo.com> > --- Thanks, queued. -- 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 >
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@vivo.com> >> >> 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@vivo.com> >> --- > > 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@linaro.org/ > > -- 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 >>
Hi, On Fri, Feb 11, 2022 at 09:53:08PM +0100, Christophe JAILLET wrote: > 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@vivo.com> > > > > > > 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@vivo.com> > > > --- > > > > 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@linaro.org/ Oops, thanks for the hint. Patch dropped. I actually missed the do_div(div, 1000000) during my review (probably should go sleeping), so div should be within safe range in the second do_div() anyways. -- Sebastian > > > > > -- 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 > > > >
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;