1 files changed, 16 insertions, 7 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);