Em Tue, 10 Feb 2015 12:57:24 +0200
Antti Palosaari <cr...@iki.fi> escreveu:
> On 02/09/2015 12:44 AM, Luis de Bethencourt wrote:
> > Cleaning the following compiler warning:
> > rtl2832.c:703:12: warning: 'tmp' may be used uninitialized in this function
> >
> > Even though it could never happen since if rtl2832_rd_demod_reg () doesn't
> > set
> > tmp, this line would never run because we go to err. It is still nice to
> > avoid
> > compiler warnings.
> >
> > Signed-off-by: Luis de Bethencourt <luis...@samsung.com>
> > ---
> > drivers/media/dvb-frontends/rtl2832.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/dvb-frontends/rtl2832.c
> > b/drivers/media/dvb-frontends/rtl2832.c
> > index 5d2d8f4..ad36d1c 100644
> > --- a/drivers/media/dvb-frontends/rtl2832.c
> > +++ b/drivers/media/dvb-frontends/rtl2832.c
> > @@ -685,7 +685,7 @@ static int rtl2832_read_status(struct dvb_frontend *fe,
> > fe_status_t *status)
> > struct rtl2832_dev *dev = fe->demodulator_priv;
> > struct i2c_client *client = dev->client;
> > int ret;
> > - u32 tmp;
> > + u32 tmp = 0;
> >
> > dev_dbg(&client->dev, "\n");
>
> I looked the code and I cannot see how it could used as uninitialized.
> Dunno how it could be fixed properly.
>
> Also, I think idiom to say compiler that variable could be uninitialized
> is to store its own value. But I am fine with zero initialization too.
>
> u32 tmp = tmp;
Actually, the right way is to declare it as:
u32 uninitialized_var(tmp)
The syntax to suppress compiler warnings depends on the compiler:
include/linux/compiler-clang.h:#define uninitialized_var(x) x = *(&(x))
include/linux/compiler-gcc.h:#define uninitialized_var(x) x = x
Also, using uninitialized_var() better documents it.
Regards,
Mauro
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