Hi Guenter,
On Sat, 24 Mar 2012 08:56:49 -0700, Guenter Roeck wrote:
> Some configurations produce the following compile warning:
>
> drivers/hwmon/adm1031.c: In function 'set_fan_auto_channel':
> drivers/hwmon/adm1031.c:292: warning: 'reg' may be used uninitialized in this function
>
> While this is a false positive, it can easily be fixed by overloading the return
> value from get_fan_auto_nearest with both register value and error return code
> (the register value is never negative). Coincidentially, that also reduces
> module size by a few bytes.
>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> drivers/hwmon/adm1031.c | 21 ++++++++-------------
> 1 files changed, 8 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/hwmon/adm1031.c b/drivers/hwmon/adm1031.c
> index ff37363..c58acb4 100644
> --- a/drivers/hwmon/adm1031.c
> +++ b/drivers/hwmon/adm1031.c
> @@ -233,18 +233,15 @@ static const auto_chan_table_t auto_channel_select_table_adm1030 = {
> * nearest match if no exact match where found.
> */
> static int
> -get_fan_auto_nearest(struct adm1031_data *data,
> - int chan, u8 val, u8 reg, u8 *new_reg)
> +get_fan_auto_nearest(struct adm1031_data *data, int chan, u8 val, u8 reg)
> {
> int i;
> int first_match = -1, exact_match = -1;
> u8 other_reg_val =
> (*data->chan_select_table)[FAN_CHAN_FROM_REG(reg)][chan ? 0 : 1];
>
> - if (val == 0) {
> - *new_reg = 0;
> + if (val == 0)
> return 0;
> - }
>
> for (i = 0; i < 8; i++) {
> if ((val == (*data->chan_select_table)[i][chan]) &&
> @@ -264,13 +261,11 @@ get_fan_auto_nearest(struct adm1031_data *data,
> }
>
> if (exact_match >= 0)
> - *new_reg = exact_match;
> + return exact_match;
> else if (first_match >= 0)
> - *new_reg = first_match;
> - else
> - return -EINVAL;
> + return first_match;
>
> - return 0;
> + return -EINVAL;
> }
>
> static ssize_t show_fan_auto_channel(struct device *dev,
> @@ -301,10 +296,10 @@ set_fan_auto_channel(struct device *dev, struct device_attribute *attr,
>
> mutex_lock(&data->update_lock);
>
> - ret = get_fan_auto_nearest(data, nr, val, data->conf1, ®);
> - if (ret) {
> + reg = get_fan_auto_nearest(data, nr, val, data->conf1);
> + if (reg < 0) {
> mutex_unlock(&data->update_lock);
> - return ret;
> + return reg;
> }
> data->conf1 = FAN_CHAN_TO_REG(reg, data->conf1);
> if ((data->conf1 & ADM1031_CONF1_AUTO_MODE) ^
Meep meep. reg is u8, it can't hold negative values. You must turn reg
into an int, or do:
ret = get_fan_auto_nearest(data, nr, val, data->conf1);
if (ret < 0) {
mutex_unlock(&data->update_lock);
return ret;
}
reg = ret;
--
Jean Delvare
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