Re: [PATCH 4/4] staging: fbtft: Avoid potential precedence issues

[DEEPAK VARMA <mh12gx2825@gmail.com>]

On Tue, Mar 17, 2020 at 12:46:14PM +0100, Greg KH wrote:
> On Mon, Mar 16, 2020 at 05:12:32AM +0530, Deepak R Varma wrote:
> > Put parentheses around uses of macro parameters to avoid possible
> > precedence issues. Problem detected by checkpatch.
> > 
> > Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
> > Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
> > ---
> >  drivers/staging/fbtft/fbtft.h | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > index 81da30f4062e..76f8c090a837 100644
> > --- a/drivers/staging/fbtft/fbtft.h
> > +++ b/drivers/staging/fbtft/fbtft.h
> > @@ -406,8 +406,8 @@ do {                                                         \
> >  
> >  #define fbtft_par_dbg(level, par, format, arg...)            \
> >  do {                                                         \
> > -	if (unlikely(par->debug & level))                    \
> > -		dev_info(par->info->device, format, ##arg);  \
> > +	if (unlikely((par)->debug & (level)))                    \
> > +		dev_info((par)->info->device, format, ##arg);  \
> 
> "precedence issues" are impossible to happen here, it's a pointer that
> we are dealing with, not some other type of expression.
> 
> So I'll take this, just to shut checkpatch up, but note that this is
> _NOT_ a real issue at all.

Thank you Greg.

> 
> And what about all of the other macros like this in this file?  Does
> only this one need the changes?

There is one more macro that accepts arguments, but its already fixed in
the past. I did not find any other macro with similar checkpatch
warning.

> 
> thanks,
> 
> greg k-h