Re: [PATCH] platform/chrome: cros_ec_uart: fix negative type promoted to high

[Dan Carpenter <error27@gmail.com>]

On Tue, Jan 17, 2023 at 04:12:40PM +0800, Tzung-Bi Shih wrote:
> On Mon, Jan 09, 2023 at 04:15:54PM +0800, Tzung-Bi Shih wrote:
> > serdev_device_write_buf() returns negative numbers on errors.  When
> > the return value compares to unsigned integer `len`, it promotes to
> > quite large positive number.
> > 
> > Fix it.
> > 
> > Fixes: 04a8bdd135cc ("platform/chrome: cros_ec_uart: Add transport layer")
> > Reported-by: Dan Carpenter <error27@gmail.com>
> > Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
> > ---
> > Reported in https://lore.kernel.org/chrome-platform/Y7fhw4S7Tb0GcHMF@kili/T/#u.
> > 
> >  drivers/platform/chrome/cros_ec_uart.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c
> > index 6916069f1599..788246559bbb 100644
> > --- a/drivers/platform/chrome/cros_ec_uart.c
> > +++ b/drivers/platform/chrome/cros_ec_uart.c
> > @@ -149,9 +149,10 @@ static int cros_ec_uart_pkt_xfer(struct cros_ec_device *ec_dev,
> >  	resp->status = 0;
> >  
> >  	ret = serdev_device_write_buf(serdev, ec_dev->dout, len);
> > -	if (ret < len) {
> > +	if (ret < 0 || ret < len) {
> >  		dev_err(ec_dev->dev, "Unable to write data\n");
> > -		ret = -EIO;
> > +		if (ret >= 0)
> > +			ret = -EIO;
> >  		goto exit;
> >  	}
> 
> Does this patch make sense to someone in the mailing list?

Yeah.  It looks fine.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>

regards,
dan carpenter