The DMA map functions can fail and should be tested for errors.
If the mapping fails, dealloc buffers, and return.

Fixes: 1c1e45d17b66 ("V4L/DVB (7786): cx18: new driver for the Conexant CX23418 MPEG encoder chip")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
---
 drivers/media/pci/cx18/cx18-queue.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/media/pci/cx18/cx18-queue.c b/drivers/media/pci/cx18/cx18-queue.c
index 013694bfcb1c..7cbb2d586932 100644
--- a/drivers/media/pci/cx18/cx18-queue.c
+++ b/drivers/media/pci/cx18/cx18-queue.c
@@ -379,15 +379,22 @@ int cx18_stream_alloc(struct cx18_stream *s)
 			break;
 		}
 
+		buf->dma_handle = dma_map_single(&s->cx->pci_dev->dev,
+						 buf->buf, s->buf_size,
+						 s->dma);
+		if (dma_mapping_error(&s->cx->pci_dev->dev, buf->dma_handle)) {
+			kfree(buf->buf);
+			kfree(mdl);
+			kfree(buf);
+			break;
+		}
+
 		INIT_LIST_HEAD(&mdl->list);
 		INIT_LIST_HEAD(&mdl->buf_list);
 		mdl->id = s->mdl_base_idx; /* a somewhat safe value */
 		cx18_enqueue(s, mdl, &s->q_idle);
 
 		INIT_LIST_HEAD(&buf->list);
-		buf->dma_handle = dma_map_single(&s->cx->pci_dev->dev,
-						 buf->buf, s->buf_size,
-						 s->dma);
 		cx18_buf_sync_for_cpu(s, buf);
 		list_add_tail(&buf->list, &s->buf_pool);
 	}
-- 
2.43.0