Re: [PATCH] checkpatch: Check for illegal return codes

[pheragu]

On 2018-07-03 11:19, Joe Perches wrote:
> On Tue, 2018-07-03 at 11:09 -0700, Prakruthi Deepak Heragu wrote:
> > The only legal integer return is 0, anything else
> > following "return" should be -ERRCODE or a function.
> >
> > http://lkml.org/lkml/2010/7/23/318
> >   There's lots of "return -1;" statements in this patch - it's obscene
> >   that this is used to indicate "some error occurred" in kernel space
> >   rather than a real errno value - even when an existing function
> >   (eg, request_irq) gave you an error code already.
> >
> > Signed-off-by: Patrick Pannuto <ppannuto@xxxxxxxxxxxxxx>
> > Signed-off-by: Stepan Moskovchenko <stepanm@xxxxxxxxxxxxxx>
> > Signed-off-by: Prakruthi Deepak Heragu <pheragu@xxxxxxxxxxxxxx>
> > ---
> >  scripts/checkpatch.pl | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index a9c0550..260d252 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -6197,6 +6197,12 @@ sub process {
> >  			     "switch default: should use break\n" . $herectx);
> >  		}
> >
> > +# check for return codes on error paths
> > +		if ($line =~ /\breturn\s+-\d+/) {
> > +			ERROR("NO_ERROR_CODE",
> > +			      "illegal return value, please use an error code");
> > +		}
> > +
>
> Substitute illegal to invalid as this wouldn't be illegal.
> It might be invalid and this needs a newline and $herecurr
>
> I'm not sure this is even useful.
>
> There are _way_ too many of these already existing
> and simple return identifiers can be OK.
>
> $ git grep -P '\breturn\s*\-(?!0)\d+' | wc -l
> 10193
>
> and
>
> $ git grep -P '\breturn\s*\-(?!1)\d+' | wc -l
> 240
True. However, this would be helpful to avoid usage of such return 
statements in the future.