[PATCH] media: pci: ivtv: Add missing check after DMA map

[Thomas Fourier <fourier.thomas@gmail.com>]

The DMA map functions can fail and should be tested for errors.
If the mapping fails, free blanking_ptr and set it to 0.  As 0 is a
valid DMA address, use blanking_ptr to test if the DMA address
is set.

Fixes: 1a0adaf37c30  ("V4L/DVB (5345): ivtv driver for Conexant cx23416/cx23415 MPEG encoder/decoder")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
---
 drivers/media/pci/ivtv/ivtv-irq.c | 2 +-
 drivers/media/pci/ivtv/ivtv-yuv.c | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/media/pci/ivtv/ivtv-irq.c b/drivers/media/pci/ivtv/ivtv-irq.c
index 748c14e87963..4d63daa01eed 100644
--- a/drivers/media/pci/ivtv/ivtv-irq.c
+++ b/drivers/media/pci/ivtv/ivtv-irq.c
@@ -351,7 +351,7 @@ void ivtv_dma_stream_dec_prepare(struct ivtv_stream *s, u32 offset, int lock)
 
 	/* Insert buffer block for YUV if needed */
 	if (s->type == IVTV_DEC_STREAM_TYPE_YUV && f->offset_y) {
-		if (yi->blanking_dmaptr) {
+		if (yi->blanking_ptr) {
 			s->sg_pending[idx].src = yi->blanking_dmaptr;
 			s->sg_pending[idx].dst = offset;
 			s->sg_pending[idx].size = 720 * 16;
diff --git a/drivers/media/pci/ivtv/ivtv-yuv.c b/drivers/media/pci/ivtv/ivtv-yuv.c
index 2d9274537725..71f040106647 100644
--- a/drivers/media/pci/ivtv/ivtv-yuv.c
+++ b/drivers/media/pci/ivtv/ivtv-yuv.c
@@ -125,7 +125,7 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma,
 	ivtv_udma_fill_sg_array(dma, y_buffer_offset, uv_buffer_offset, y_size);
 
 	/* If we've offset the y plane, ensure top area is blanked */
-	if (f->offset_y && yi->blanking_dmaptr) {
+	if (f->offset_y && yi->blanking_ptr) {
 		dma->SGarray[dma->SG_length].size = cpu_to_le32(720*16);
 		dma->SGarray[dma->SG_length].src = cpu_to_le32(yi->blanking_dmaptr);
 		dma->SGarray[dma->SG_length].dst = cpu_to_le32(IVTV_DECODER_OFFSET + yuv_offset[frame]);
@@ -929,6 +929,12 @@ static void ivtv_yuv_init(struct ivtv *itv)
 		yi->blanking_dmaptr = dma_map_single(&itv->pdev->dev,
 						     yi->blanking_ptr,
 						     720 * 16, DMA_TO_DEVICE);
+		if (dma_mapping_error(&itv->pdev->dev, yi->blanking_dmaptr)) {
+			kfree(yi->blanking_ptr);
+			yi->blanking_ptr = NULL;
+			yi->blanking_dmaptr = 0;
+			IVTV_DEBUG_WARN("Failed to dma_map yuv blanking buffer\n");
+		}
 	} else {
 		yi->blanking_dmaptr = 0;
 		IVTV_DEBUG_WARN("Failed to allocate yuv blanking buffer\n");
-- 
2.43.0