Re: [PATCH] iio: adc: pac1921: add missing error return in probe()

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 11 Sep 2024 11:32:04 +0200
Matteo Martelli <matteomartelli3@gmail.com> wrote:

> Quoting Jonathan Cameron (2024-08-10 12:35:18)
> > On Fri, 9 Aug 2024 18:18:13 +0300
> > Dan Carpenter <dan.carpenter@linaro.org> wrote:
> >   
> > > On Fri, Aug 09, 2024 at 09:31:43AM +0200, Matteo Martelli wrote:  
> > > > Christophe JAILLET wrote:    
> > > > > Le 08/08/2024 à 21:28, Dan Carpenter a écrit :    
> > > > > > This error path was intended to return, and not just print an error.  The
> > > > > > current code will lead to an error pointer dereference.
> > > > > > 
> > > > > > Fixes: 371f778b83cd ("iio: adc: add support for pac1921")
> > > > > > Signed-off-by: Dan Carpenter <dan.carpenter-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> > > > > > ---
> > > > > >   drivers/iio/adc/pac1921.c | 4 ++--
> > > > > >   1 file changed, 2 insertions(+), 2 deletions(-)
> > > > > > 
> > > > > > diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c
> > > > > > index d04c6685d780..8200a47bdf21 100644
> > > > > > --- a/drivers/iio/adc/pac1921.c
> > > > > > +++ b/drivers/iio/adc/pac1921.c
> > > > > > @@ -1168,8 +1168,8 @@ static int pac1921_probe(struct i2c_client *client)
> > > > > >   
> > > > > >         priv->regmap = devm_regmap_init_i2c(client, &pac1921_regmap_config);
> > > > > >         if (IS_ERR(priv->regmap))
> > > > > > -               dev_err_probe(dev, (int)PTR_ERR(priv->regmap),
> > > > > > -                             "Cannot initialize register map\n");
> > > > > > +               return dev_err_probe(dev, (int)PTR_ERR(priv->regmap),    
> > > > > 
> > > > > The (int) is unusual.
> > > > >    
> > > > The (int) explicit cast is to address Wconversion warnings since dev_err_probe
> > > > takes an int as argument.    
> > > 
> > > I don't want to remove the int because it's unrelated, but Christophe is right
> > > that the int is unusual.  We really would want to discourage that.  
> > 
> > Applied, but I'd ideally like a follow up patch removing the int and the
> > couple of similar instances from this driver.  Anyone want to spin one?
> >   
> 
> I can spin the patch, but at this point I am wondering whether I should remove all
> the unnecessary explicit casts that I put to address Wconversion
> and Wsign-compare warnings. If that's the general approach to help readability I
> am totally fine with it.

I think it is probably sensible to do so as mostly we know the value ranges
etc so they don't matter.

Jonathan

> 
> > Thanks,
> > 
> > Jonathan
> >   
> 
> Thanks,
> Matteo Martelli