iio: adc: viperboard: Fix error handling in vprbrd_iio_read_raw

The driver proceeds to the reception phase even if the preceding
transmission fails.

This uses a goto error label for an early bail out and ensures the mutex is
properly unlocked in case of failure.

Fixes: ffd8a6e7a778 ("iio: adc: Add viperboard adc driver")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Reviewed-by: Maxwell Doose <m32285159@gmail.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/adc/viperboard_adc.c b/drivers/iio/adc/viperboard_adc.c
index 9bb0b83c8f6764d83bd2c38a3cc1b2d865998cb5..6efe1c618ef7171a7c151a239ac2889d957c102b 100644 (file)
--- a/drivers/iio/adc/viperboard_adc.c
+++ b/drivers/iio/adc/viperboard_adc.c
@@ -70,8 +70,10 @@ static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
                        VPRBRD_USB_TYPE_OUT, 0x0000, 0x0000, admsg,
                        sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
                if (ret != sizeof(struct vprbrd_adc_msg)) {
-                       dev_err(&iio_dev->dev, "usb send error on adc read\n");
+                       mutex_unlock(&vb->lock);
                        error = -EREMOTEIO;
+                       dev_err(&iio_dev->dev, "usb send error on adc read\n");
+                       goto error;
                }
 
                ret = usb_control_msg(vb->usb_dev,