Re: [PATCH] soundwire: qcom: use signed variable for error return

[Vinod Koul]

On 31-03-21, 09:41, Pierre-Louis Bossart wrote:
> 
> 
> On 3/31/21 2:21 AM, Vinod Koul wrote:
> > We get warning for using a unsigned variable being compared to less than
> > zero. The comparison is correct as it checks for errors from previous
> > call to qcom_swrm_get_alert_slave_dev_num(), so we should use a signed
> > variable instead.
> > 
> > drivers/soundwire/qcom.c: qcom_swrm_irq_handler() warn: impossible
> > condition '(devnum < 0) => (0-255 < 0)'
> > 
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
> > ---
> >   drivers/soundwire/qcom.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> > index b08ecb9b418c..55ed133c6704 100644
> > --- a/drivers/soundwire/qcom.c
> > +++ b/drivers/soundwire/qcom.c
> > @@ -428,7 +428,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
> >   	struct qcom_swrm_ctrl *swrm = dev_id;
> >   	u32 value, intr_sts, intr_sts_masked, slave_status;
> >   	u32 i;
> > -	u8 devnum = 0;
> > +	s8 devnum = 0;
> 
> it's not great to store negative error codes with s8. That works in this
> specific case because the function only returns -EINVAL.

Yeah I did check EINVAL was the case which would work but in general I
agree that makes sense, I discussed with Srini on IRC and looks like I
havent posted v2, should hit the pipes shortly

-- 
~Vinod