2 files changed, 21 insertions, 10 deletions

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 7d77e4d30c8a..44cd0e530bbd 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -267,8 +267,14 @@ static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
 
 	/* release the scatterlist cache */
 	if (attach->dma_dir != DMA_NONE)
-		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-			attach->dma_dir);
+		/*
+		 * Cache sync can be skipped here, as the vb2_dc memory is
+		 * allocated from device coherent memory, which means the
+		 * memory locations do not require any explicit cache
+		 * maintenance prior or after being used by the device.
+		 */
+		dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+				   attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 	sg_free_table(sgt);
 	kfree(attach);
 	db_attach->priv = NULL;
@@ -293,14 +299,17 @@ static struct sg_table *vb2_dc_dmabuf_ops_map(
 
 	/* release any previous cache */
 	if (attach->dma_dir != DMA_NONE) {
-		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-			attach->dma_dir);
+		dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+				   attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 		attach->dma_dir = DMA_NONE;
 	}
 
-	/* mapping to the client with new direction */
-	sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-				dma_dir);
+	/*
+	 * mapping to the client with new direction, no cache sync
+	 * required see comment in vb2_dc_dmabuf_ops_detach()
+	 */
+	sgt->nents = dma_map_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+				      dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 	if (!sgt->nents) {
 		pr_err("failed to map scatterlist\n");
 		mutex_unlock(lock);
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 40d76eb4c2fe..5a9ba3846f0a 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -872,17 +872,19 @@ EXPORT_SYMBOL_GPL(vb2_queue_release);
 __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
 {
 	struct video_device *vfd = video_devdata(file);
-	__poll_t res = 0;
+	__poll_t res;
+
+	res = vb2_core_poll(q, file, wait);
 
 	if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
 		struct v4l2_fh *fh = file->private_data;
 
 		poll_wait(file, &fh->wait, wait);
 		if (v4l2_event_pending(fh))
-			res = EPOLLPRI;
+			res |= EPOLLPRI;
 	}
 
-	return res | vb2_core_poll(q, file, wait);
+	return res;
 }
 EXPORT_SYMBOL_GPL(vb2_poll);