[PATCH v2 3/4] iio: accel: kionix-kx022a: Prevent memory leak and fix state

From: Matti Vaittinen <[email protected]>

The driver allocates memory for samples at buffer enable path. If regmap
operation fails in the kx022a_fifo_enable() at the buffer enable path, the
allocated memory is never freed. Furthermore, the state information and
previous hardware configuration(s) aren't undone, potentially leaving
WMI interrupts and buffers enabled, or driver state flags wrong.

Free the memory and revert the hardware configuration and state flags on
error path.

Fixes: e7123a4dfcd7 ("iio: accel: kionix-kx022a: Refactor driver and add chip_info structure")
Signed-off-by: Matti Vaittinen <[email protected]>
Reviewed-by: Mehdi Djait <[email protected]>

---
Revision history:
v1 => v2:
 - Fix unwinding the fifo enabling
 - Move Fixes before the SOB.
---
 drivers/iio/accel/kionix-kx022a.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c
index 8a13f78aeab0..fa94bc0fd8cf 100644
--- a/drivers/iio/accel/kionix-kx022a.c
+++ b/drivers/iio/accel/kionix-kx022a.c
@@ -980,26 +980,44 @@ static int kx022a_fifo_enable(struct kx022a_data *data)
 	guard(mutex)(&data->mutex);
 	ret = __kx022a_turn_on_off(data, false);
 	if (ret)
-		return ret;
+		goto err_free_out;
 
 	/* Update watermark to HW */
 	ret = kx022a_fifo_set_wmi(data);
 	if (ret)
-		return ret;
+		goto err_wmi_out;
 
 	/* Enable buffer */
 	ret = regmap_set_bits(data->regmap, data->chip_info->buf_cntl2,
 			      KX022A_MASK_BUF_EN);
 	if (ret)
-		return ret;
+		goto err_wmi_out;
 
 	data->state |= KX022A_STATE_FIFO;
 	ret = regmap_set_bits(data->regmap, data->ien_reg,
 			      KX022A_MASK_WMI);
 	if (ret)
-		return ret;
+		goto err_buf_en_out;
 
-	return __kx022a_turn_on_off(data, true);
+	ret = __kx022a_turn_on_off(data, true);
+	if (ret)
+		goto err_on_out;
+
+	return ret;
+
+err_on_out:
+	regmap_clear_bits(data->regmap, data->ien_reg,
+			  KX022A_MASK_WMI);
+err_buf_en_out:
+	regmap_clear_bits(data->regmap, data->chip_info->buf_cntl2,
+			  KX022A_MASK_BUF_EN);
+	data->state &= ~KX022A_STATE_FIFO;
+err_wmi_out:
+	__kx022a_turn_on_off(data, true);
+err_free_out:
+	kfree(data->fifo_buffer);
+
+	return ret;
 }
 
 static int kx022a_buffer_postenable(struct iio_dev *idev)
-- 
2.55.0

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