[PATCH 21/38] iio: sensors-core: st: Clean-up error handling in st_sensors_read_axis_data()

Lee Jones
2013-09-16T08:22:17Z

On Sat, 14 Sep 2013, Jonathan Cameron wrote:

> On 09/10/13 13:49, Lee Jones wrote:
> > Gets rid of those unnecessary gotos.
>
> Unfortunately it introduced a bug whilst it is at it. Sometimes
> those gotos are necessary and the 'right' way to do things.
> >
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> > drivers/iio/common/st_sensors/st_sensors_core.c | 17 +++++++----------
> > 1 file changed, 7 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
> > index 8c4c54c..148f0e5 100644
> > --- a/drivers/iio/common/st_sensors/st_sensors_core.c
> > +++ b/drivers/iio/common/st_sensors/st_sensors_core.c
> > @@ -331,26 +331,23 @@ static int st_sensors_read_axis_data(struct iio_dev *indio_dev,
> > unsigned int byte_for_channel = ch->scan_type.storagebits >> 3;
> >
> > outdata = kmalloc(byte_for_channel, GFP_KERNEL);
> > - if (!outdata) {
> > - err = -EINVAL;
> > - goto st_sensors_read_axis_data_error;
> > - }
> > + if (!outdata)
> > + return -ENOMEM;
> I agree this change makes complete sense.
> >
> > err = sdata->tf->read_multiple_byte(&sdata->tb, sdata->dev,
> > ch->address, byte_for_channel,
> > outdata, sdata->multiread_bit);
> > - if (err < 0)
> > - goto st_sensors_free_memory;
> > + if (err < 0) {
> > + kfree(outdata);
> > + return err;
> > + }
> I don't like this change as....
> >
> > if (byte_for_channel == 2)
> > *data = (s16)get_unaligned_le16(outdata);
> > else if (byte_for_channel == 3)
> > *data = (s32)st_sensors_get_unaligned_le24(outdata);
> >
> > -st_sensors_free_memory:
> > - kfree(outdata);
> you now don't free out data in the case of no error. This is precisely the case
> where a goto is the correct way to handle things as the free need to occur whether
> or not the error occurs.

Ah, you're quite right. I'll fix up.

> > -st_sensors_read_axis_data_error:
> > - return err;
> > + return 0;
> > }
> >
> > int st_sensors_read_info_raw(struct iio_dev *indio_dev,
> >

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
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