Re: [PATCH 1/3] Input: elan_i2c_smbus - cast sizeof to int for comparison

Dmitry Torokhov
2018-08-01T23:03:54Z

On Sun, Jul 01, 2018 at 07:32:03PM +0200, Julia Lawall wrote:
> Comparing an int to a size, which is unsigned, causes the int to become
> unsigned, giving the wrong result. i2c_smbus_read_block_data can return the
> result of i2c_smbus_xfer, whih can return a negative error code.
>
> A simplified version of the semantic match that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @@
> int x;
> expression e,e1;
> identifier f;
> @@
>
> *x = f(...);
> ... when != x = e1
> when != if (x < 0 || ...) { ... return ...; }
> *x < sizeof(e)
> // </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>

Applied, thank you.

> ---
> drivers/input/mouse/elan_i2c_smbus.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/input/mouse/elan_i2c_smbus.c b/drivers/input/mouse/elan_i2c_smbus.c
> index c060d27..88e315d 100644
> --- a/drivers/input/mouse/elan_i2c_smbus.c
> +++ b/drivers/input/mouse/elan_i2c_smbus.c
> @@ -387,7 +387,7 @@ static int elan_smbus_prepare_fw_update(struct i2c_client *client)
> len = i2c_smbus_read_block_data(client,
> ETP_SMBUS_IAP_PASSWORD_READ,
> val);
> - if (len < sizeof(u16)) {
> + if (len < (int)sizeof(u16)) {
> error = len < 0 ? len : -EIO;
> dev_err(dev, "failed to read iap password: %d\n",
> error);
>

--
Dmitry