linux-kernel - Re: [PATCH] Input: cyapa - Remove superfluous type check in cyapa_gen5_read_idac

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Message-ID: <20150302174059.GD17094@dtor-ws>
Date:	Mon, 2 Mar 2015 09:40:59 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Dudley Du <dudl@...ress.com>
Cc:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Input: cyapa - Remove superfluous type check in
 cyapa_gen5_read_idac_data()

On Mon, Mar 02, 2015 at 04:20:34AM +0000, Dudley Du wrote:
> Thanks for the check.
> This fix is verified okay.

Applied, thank you.

> 
> Dudley
> 
> > -----Original Message-----
> > From: Geert Uytterhoeven [mailto:geert@...ux-m68k.org]
> > Sent: 2015年2月12日 22:16
> > To: Dmitry Torokhov; Dudley Du
> > Cc: linux-input@...r.kernel.org; linux-kernel@...r.kernel.org; Geert Uytterhoeven
> > Subject: [PATCH] Input: cyapa - Remove superfluous type check in
> > cyapa_gen5_read_idac_data()
> >
> > drivers/input/mouse/cyapa_gen5.c: In function ‘cyapa_gen5_read_idac_data’:
> > drivers/input/mouse/cyapa_gen5.c:1876: warning: ‘max_element_cnt’ may be
> > used uninitialized in this function
> > drivers/input/mouse/cyapa_gen5.c:1873: warning: ‘offset’ may be used
> > uninitialized in this function
> >
> > If *data_size is non-zero, and idac_data_type contains an unknown type,
> > max_element_cnt and offset will be uninitialized, and the loop will
> > process non-existing data.
> >
> > However, this cannot happen (for now), as there's a test for unknown
> > types at the top of cyapa_gen5_read_idac_data().
> >
> > As no "if ... else if ..." is used in other places, remove the
> > superfluous "if" to silence the compiler warning.
> >
> > Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> > ---
> > Alternatively, we can pre-initialize max_element_cnt and offset to zero,
> > and add "if (!max_element_cnt) goto out;" before the loop.
> >
> >  drivers/input/mouse/cyapa_gen5.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/input/mouse/cyapa_gen5.c b/drivers/input/mouse/cyapa_gen5.c
> > index ddf5393a118098fc..88c465b70e9d8776 100644
> > --- a/drivers/input/mouse/cyapa_gen5.c
> > +++ b/drivers/input/mouse/cyapa_gen5.c
> > @@ -1926,7 +1926,7 @@ static int cyapa_gen5_read_idac_data(struct cyapa
> > *cyapa,
> >  electrodes_tx = cyapa->electrodes_x;
> >  max_element_cnt = ((cyapa->aligned_electrodes_rx + 7) &
> >  ~7u) * electrodes_tx;
> > -} else if (idac_data_type == GEN5_RETRIEVE_SELF_CAP_PWC_DATA) {
> > +} else {
> >  offset = 2;
> >  max_element_cnt = cyapa->electrodes_x +
> >  cyapa->electrodes_y;
> > --
> > 1.9.1
> 
> 
> This message and any attachments may contain Cypress (or its subsidiaries) confidential information. If it has been received in error, please advise the sender and immediately delete this message.

-- 
Dmitry
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