Fix for:
drivers/staging/iio/gyro/adis16080_core.c: In function
‘adis16080_read_raw’:
drivers/staging/iio/gyro/adis16080_core.c:99:8: warning: ‘ut’
may be used uninitialized in this function [-Wuninitialized]
Initialize ut and change error handling from adis16080_read_raw().
Signed-off-by: Danny Kukawka <[email protected]>
---
drivers/staging/iio/gyro/adis16080_core.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/iio/gyro/adis16080_core.c b/drivers/staging/iio/gyro/adis16080_core.c
index 1815490..e0b2a29 100644
--- a/drivers/staging/iio/gyro/adis16080_core.c
+++ b/drivers/staging/iio/gyro/adis16080_core.c
@@ -82,7 +82,7 @@ static int adis16080_read_raw(struct iio_dev *indio_dev,
long mask)
{
int ret = -EINVAL;
- u16 ut;
+ u16 ut = 0;
/* Take the iio_dev status lock */
mutex_lock(&indio_dev->mlock);
@@ -94,7 +94,7 @@ static int adis16080_read_raw(struct iio_dev *indio_dev,
if (ret < 0)
break;
ret = adis16080_spi_read(indio_dev, &ut);
- if (ret < 0)
+ if (ret)
break;
*val = ut;
ret = IIO_VAL_INT;
--
1.7.7.3
On Tue, Feb 14, 2012 at 03:35:36PM +0100, Danny Kukawka wrote:
> Fix for:
> drivers/staging/iio/gyro/adis16080_core.c: In function
> ‘adis16080_read_raw’:
> drivers/staging/iio/gyro/adis16080_core.c:99:8: warning: ‘ut’
> may be used uninitialized in this function [-Wuninitialized]
>
> Initialize ut and change error handling from adis16080_read_raw().
>
> Signed-off-by: Danny Kukawka <[email protected]>
> ---
> drivers/staging/iio/gyro/adis16080_core.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/iio/gyro/adis16080_core.c b/drivers/staging/iio/gyro/adis16080_core.c
> index 1815490..e0b2a29 100644
> --- a/drivers/staging/iio/gyro/adis16080_core.c
> +++ b/drivers/staging/iio/gyro/adis16080_core.c
> @@ -82,7 +82,7 @@ static int adis16080_read_raw(struct iio_dev *indio_dev,
> long mask)
> {
> int ret = -EINVAL;
> - u16 ut;
> + u16 ut = 0;
> /* Take the iio_dev status lock */
>
> mutex_lock(&indio_dev->mlock);
> @@ -94,7 +94,7 @@ static int adis16080_read_raw(struct iio_dev *indio_dev,
> if (ret < 0)
> break;
> ret = adis16080_spi_read(indio_dev, &ut);
> - if (ret < 0)
> + if (ret)
> break;
Either one of these changes would silence the warning from gcc
(which is a false positive). I would keep the "ut = 0;" change and
leave the error handling the same. That way we check for less than
zero consistently instead of checking some for non-zero and some for
less than zero.
I normally wouldn't have commented on this if the changelog had said
whether it was a gcc false positive or if the code changes the
behavior. It really should be mentioned.
If you could put a "Staging:" and an "iio" in the subject, that
would be grand as well. Everyone seems to be using the prefix
"staging:iio:gyro:adis16080" for that file... I don't know why they
don't just use slashes if they're going to specify the whole file...
regards,
dan carpenter
On 2/14/2012 3:04 PM, Dan Carpenter wrote:
> On Tue, Feb 14, 2012 at 03:35:36PM +0100, Danny Kukawka wrote:
>> Fix for:
>> drivers/staging/iio/gyro/adis16080_core.c: In function
>> ‘adis16080_read_raw’:
>> drivers/staging/iio/gyro/adis16080_core.c:99:8: warning: ‘ut’
>> may be used uninitialized in this function [-Wuninitialized]
>>
>> Initialize ut and change error handling from adis16080_read_raw().
>>
>> Signed-off-by: Danny Kukawka<[email protected]>
>> ---
>> drivers/staging/iio/gyro/adis16080_core.c | 4 ++--
>> 1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/iio/gyro/adis16080_core.c b/drivers/staging/iio/gyro/adis16080_core.c
>> index 1815490..e0b2a29 100644
>> --- a/drivers/staging/iio/gyro/adis16080_core.c
>> +++ b/drivers/staging/iio/gyro/adis16080_core.c
>> @@ -82,7 +82,7 @@ static int adis16080_read_raw(struct iio_dev *indio_dev,
>> long mask)
>> {
>> int ret = -EINVAL;
>> - u16 ut;
>> + u16 ut = 0;
>> /* Take the iio_dev status lock */
>>
>> mutex_lock(&indio_dev->mlock);
>> @@ -94,7 +94,7 @@ static int adis16080_read_raw(struct iio_dev *indio_dev,
>> if (ret< 0)
>> break;
>> ret = adis16080_spi_read(indio_dev,&ut);
>> - if (ret< 0)
>> + if (ret)
>> break;
> Either one of these changes would silence the warning from gcc
> (which is a false positive). I would keep the "ut = 0;" change and
> leave the error handling the same. That way we check for less than
> zero consistently instead of checking some for non-zero and some for
> less than zero.
Agreed. I've always been lazy on this one as it was a false positive,
but might as well
get rid of it...
>
> I normally wouldn't have commented on this if the changelog had said
> whether it was a gcc false positive or if the code changes the
> behavior. It really should be mentioned.
>
> If you could put a "Staging:" and an "iio" in the subject, that
> would be grand as well. Everyone seems to be using the prefix
> "staging:iio:gyro:adis16080" for that file... I don't know why they
> don't just use slashes if they're going to specify the whole file...
Fair point. Ah well, habits die hard. Sometimes we have things like
staging:iio:treewide which is probably why I started doing this...
On Dienstag, 14. Februar 2012, Jonathan Cameron wrote:
> On 2/14/2012 3:04 PM, Dan Carpenter wrote:
> > On Tue, Feb 14, 2012 at 03:35:36PM +0100, Danny Kukawka wrote:
> >> Fix for:
> >> drivers/staging/iio/gyro/adis16080_core.c: In function
> >> ‘adis16080_read_raw’:
> >> drivers/staging/iio/gyro/adis16080_core.c:99:8: warning: ‘ut’
> >> may be used uninitialized in this function [-Wuninitialized]
> >>
> >> Initialize ut and change error handling from adis16080_read_raw().
> >>
> >> Signed-off-by: Danny Kukawka<[email protected]>
> >> ---
> >> drivers/staging/iio/gyro/adis16080_core.c | 4 ++--
> >> 1 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/staging/iio/gyro/adis16080_core.c
> >> b/drivers/staging/iio/gyro/adis16080_core.c index 1815490..e0b2a29
> >> 100644
> >> --- a/drivers/staging/iio/gyro/adis16080_core.c
> >> +++ b/drivers/staging/iio/gyro/adis16080_core.c
> >> @@ -82,7 +82,7 @@ static int adis16080_read_raw(struct iio_dev
> >> *indio_dev, long mask)
> >> {
> >> int ret = -EINVAL;
> >> - u16 ut;
> >> + u16 ut = 0;
> >> /* Take the iio_dev status lock */
> >>
> >> mutex_lock(&indio_dev->mlock);
> >> @@ -94,7 +94,7 @@ static int adis16080_read_raw(struct iio_dev
> >> *indio_dev, if (ret< 0)
> >> break;
> >> ret = adis16080_spi_read(indio_dev,&ut);
> >> - if (ret< 0)
> >> + if (ret)
> >> break;
> >
> > Either one of these changes would silence the warning from gcc
> > (which is a false positive). I would keep the "ut = 0;" change and
> > leave the error handling the same. That way we check for less than
> > zero consistently instead of checking some for non-zero and some for
> > less than zero.
>
> Agreed. I've always been lazy on this one as it was a false positive,
> but might as well
> get rid of it...
I'm okay with 'ut = 0;'.
I guess it's hard for gcc to find out that spi_read() will only return 0 or a
negative value in error case. That's why gcc may assume 'ut' could be used
initialized since adis16080_spi_read() may return with a value > 0.
And in case spi_read() or one of the functions behind would change it could
cause an initialized 'ut'. The code may should always check for "ret != 0" as
already done in some other places (in similar cases) to be save.
Danny