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

On Sat, 14 Sep 2013, Jonathan Cameron wrote:

On 09/10/13 13:49, Lee Jones wrote:

quoted

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.

quoted

Signed-off-by: Lee Jones <redacted>
---
 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.

quoted

 
 	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....

quoted

 
 	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.

quoted

-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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