media: videobuf2-dma-sg: fix vmap callback

For dmabuf import users to be able to use the vaddr from another
videobuf2-dma-sg source, the exporter needs to set a proper vaddr on
vb2_dma_sg_dmabuf_ops_vmap callback. This patch adds vmap on map if
buf->vaddr was not set.

Cc: stable@kernel.org
Fixes: 7938f421 ("dma-buf-map: Rename to iosys-map")
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Acked-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/common/videobuf2/videobuf2-dma-sg.c

@@ -487,9 +487,15 @@ vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
 static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf,
 				      struct iosys_map *map)
 {
-	struct vb2_dma_sg_buf *buf = dbuf->priv;
+	struct vb2_dma_sg_buf *buf;
+	void *vaddr;
+
+	buf = dbuf->priv;
+	vaddr = vb2_dma_sg_vaddr(buf->vb, buf);
+	if (!vaddr)
+		return -EINVAL;
 
-	iosys_map_set_vaddr(map, buf->vaddr);
+	iosys_map_set_vaddr(map, vaddr);
 
 	return 0;
 }