[PATCH v6 2/5] media: imx-jpeg: Reset slot data pointers when freed

[ming.qian at oss.nxp.com]

From: Ming Qian <ming.qian at oss.nxp.com>

Ensure that the slot data pointers are reset to NULL and handles are
set to 0 after freeing the coherent memory. This makes he function
mxc_jpeg_alloc_slot_data() and mxc_jpeg_free_slot_data() safe to be
called multiple times.

Fixes: 2db16c6ed72c ("media: imx-jpeg: Add V4L2 driver for i.MX8 JPEG Encoder/Decoder")
Signed-off-by: Ming Qian <ming.qian at oss.nxp.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
---
v6
- Improve commit message

v5
- Split the resetting pointer when freed to a separate patch
---
 drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
index ad2284e87985..29d3d4b08dd1 100644
--- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
+++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
@@ -758,16 +758,22 @@ static void mxc_jpeg_free_slot_data(struct mxc_jpeg_dev *jpeg)
 	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
 			  jpeg->slot_data.desc,
 			  jpeg->slot_data.desc_handle);
+	jpeg->slot_data.desc = NULL;
+	jpeg->slot_data.desc_handle = 0;
 
 	/* free descriptor for encoder configuration phase / decoder DHT */
 	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
 			  jpeg->slot_data.cfg_desc,
 			  jpeg->slot_data.cfg_desc_handle);
+	jpeg->slot_data.cfg_desc_handle = 0;
+	jpeg->slot_data.cfg_desc = NULL;
 
 	/* free configuration stream */
 	dma_free_coherent(jpeg->dev, MXC_JPEG_MAX_CFG_STREAM,
 			  jpeg->slot_data.cfg_stream_vaddr,
 			  jpeg->slot_data.cfg_stream_handle);
+	jpeg->slot_data.cfg_stream_vaddr = NULL;
+	jpeg->slot_data.cfg_stream_handle = 0;
 
 	jpeg->slot_data.used = false;
 }
-- 
2.43.0-rc1