linux-kernel - Re: [lvc-project] [PATCH] Input: trackpoint

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Date:   Fri, 17 Mar 2023 03:18:20 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Andi Shyti <andi.shyti@...nel.org>
Cc:     Igor Artemiev <Igor.A.Artemiev@...t.ru>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        lvc-project@...uxtesting.org
Subject: Re: [lvc-project] [PATCH] Input: trackpoint - remove unreachable code

On Tue, Mar 14, 2023 at 02:13:56PM +0100, Andi Shyti wrote:
> Hi Igor,
> 
> On Tue, Mar 14, 2023 at 03:27:14PM +0300, Igor Artemiev wrote:
> > The trackpoint_sync() function always returnd 0.
> > And there is no need to check its result.
> > 
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: 2a924d71794c ("Input: trackpoint - only expose supported controls for Elan, ALPS and NXP")
> > Signed-off-by: Igor Artemiev <Igor.A.Artemiev@...t.ru>
> 
> I don't think it requires the Fixes tag... it's not really
> broken.
> 
> > ---
> >  drivers/input/mouse/trackpoint.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/drivers/input/mouse/trackpoint.c b/drivers/input/mouse/trackpoint.c
> > index 4a86b3e31d3b..561a4d2d81ff 100644
> > --- a/drivers/input/mouse/trackpoint.c
> > +++ b/drivers/input/mouse/trackpoint.c
> > @@ -386,9 +386,7 @@ static int trackpoint_reconnect(struct psmouse *psmouse)
> >  	was_reset = tp->variant_id == TP_VARIANT_IBM &&
> >  		    trackpoint_power_on_reset(&psmouse->ps2dev) == 0;
> >  
> > -	error = trackpoint_sync(psmouse, was_reset);
> > -	if (error)
> > -		return error;
> > +	trackpoint_sync(psmouse, was_reset);
> 
> what worries me here is that if this returns always '0' who tells
> me that it will always return '0'?
> 
> One day someone might add an error return path and you would miss
> it here.
> 
> Would it make sense to make the trackpoint_sync() a void function
> as well?

Yes if we are dropping the check we should also change the function to
not return anything.

Thanks.

-- 
Dmitry