Re: [PATCH] misc: isl29020: fix signedness bug

Andrew Morton
2010-10-29T22:17:16Z

On Thu, 28 Oct 2010 15:14:03 +0400
Vasiliy Kulikov <segooon@gmail.com> wrote:

> i2c_smbus_write_byte_data() may return negative error code. This is not
> seen to als_sensing_range_store() as the result is stored in unsigned int.
> Made it signed.
>
> Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
> ---
> Compile tested.
>
> drivers/misc/isl29020.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/misc/isl29020.c b/drivers/misc/isl29020.c
> index 34fe835..629d31e 100644
> --- a/drivers/misc/isl29020.c
> +++ b/drivers/misc/isl29020.c
> @@ -87,7 +87,7 @@ static ssize_t als_sensing_range_store(struct device *dev,
> struct device_attribute *attr, const char *buf, size_t count)
> {
> struct i2c_client *client = to_i2c_client(dev);
> - unsigned int ret_val;
> + int ret_val;
> unsigned long val;
>
> if (strict_strtoul(buf, 10, &val))

yup.

It also needs this:

drivers/misc/isl29020.c: don't ignore the i2c_smbus_read_byte_data() return value

From: Andrew Morton <akpm@linux-foundation.org>

If i2c_smbus_read_byte_data() fails, this driver will write a mangled
errno value into the hardware.

Cc: Vasiliy Kulikov <segooon@gmail.com>
Cc: Liu Hong <hong.liu@intel.com>
Cc: Kalhan Trisal <kalhan.trisal@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

drivers/misc/isl29020.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff -puN drivers/misc/isl29020.c~a drivers/misc/isl29020.c
--- a/drivers/misc/isl29020.c~a
+++ a/drivers/misc/isl29020.c
@@ -106,8 +106,10 @@ static ssize_t als_sensing_range_store(s
val = 4;

ret_val = i2c_smbus_read_byte_data(client, 0x00);
+ if (ret_val < 0)
+ return ret_val;

- ret_val &= 0xFC; /*reset the bit before setting them */
+ ret_val &= 0xFC; /* reset the bit before setting them */
ret_val |= val - 1;
ret_val = i2c_smbus_write_byte_data(client, 0x00, ret_val);

_