Hi Maira,
On Thu, Jul 27, 2023 at 11:01:27AM -0300, Maira Canal wrote:
> Hi Nathan,
>
> On 7/18/23 18:44, Nathan Chancellor wrote:
> > A proposed update to clang's -Wconstant-logical-operand to warn when the
> > left hand side is a constant shows the following instance in
> > nsecs_to_jiffies_timeout() when NSEC_PER_SEC is not a multiple of HZ,
> > such as CONFIG_HZ=300:
> >
> > In file included from drivers/gpu/drm/v3d/v3d_debugfs.c:12:
> > drivers/gpu/drm/v3d/v3d_drv.h:343:24: warning: use of logical '&&' with
> > constant operand [-Wconstant-logical-operand]
> > 343 | if (NSEC_PER_SEC % HZ &&
> > | ~~~~~~~~~~~~~~~~~ ^
> > drivers/gpu/drm/v3d/v3d_drv.h:343:24: note: use '&' for a bitwise
> > operation
> > 343 | if (NSEC_PER_SEC % HZ &&
> > | ^~
> > | &
> > drivers/gpu/drm/v3d/v3d_drv.h:343:24: note: remove constant to silence
> > this warning
> > 1 warning generated.
> >
> > Turn this into an explicit comparison against zero to make the
> > expression a boolean to make it clear this should be a logical check,
> > not a bitwise one.
> >
> > Link: https://reviews.llvm.org/D142609
> > Signed-off-by: Nathan Chancellor <nat...@kernel.org>
>
> Reviewed-by: Maíra Canal <mca...@igalia.com>
>
> Thanks for all the hard work with clang! Let me know if you need someone
> to push it to drm-misc-next.
Yes I will, I do not have drm commit rights. I think the i915 patch can
go to drm-misc as well with Tvrtko's ack. Thanks a lot for taking a
look!
Cheers,
Nathan
> Best Regards,
> - Maíra
>
> > ---
> > drivers/gpu/drm/v3d/v3d_drv.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
> > index b74b1351bfc8..7f664a4b2a75 100644
> > --- a/drivers/gpu/drm/v3d/v3d_drv.h
> > +++ b/drivers/gpu/drm/v3d/v3d_drv.h
> > @@ -340,7 +340,7 @@ struct v3d_submit_ext {
> > static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)
> > {
> > /* nsecs_to_jiffies64() does not guard against overflow */
> > - if (NSEC_PER_SEC % HZ &&
> > + if ((NSEC_PER_SEC % HZ) != 0 &&
> > div_u64(n, NSEC_PER_SEC) >= MAX_JIFFY_OFFSET / HZ)
> > return MAX_JIFFY_OFFSET;
> >
