drm: Push dirtyfb ioctl kms locking down to drivers

Not all drivers will need take all the modeset locks for dirtyfb, so
push the locking down to the drivers.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 5e827c2..b8f3bc7 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -399,10 +399,14 @@
 	struct qxl_bo *qobj;
 	int inc = 1;
 
+	drm_modeset_lock_all(fb->dev);
+
 	qobj = gem_to_qxl_bo(qxl_fb->obj);
 	/* if we aren't primary surface ignore this */
-	if (!qobj->is_primary)
+	if (!qobj->is_primary) {
+		drm_modeset_unlock_all(fb->dev);
 		return 0;
+	}
 
 	if (!num_clips) {
 		num_clips = 1;
@@ -417,6 +421,9 @@
 
 	qxl_draw_dirty_fb(qdev, qxl_fb, qobj, flags, color,
 			  clips, num_clips, inc);
+
+	drm_modeset_unlock_all(fb->dev);
+
 	return 0;
 }