drm: remove the dma_ioctl special-case

We might as well have a real ioctl function which checks for the
callbacks. This seems to be a remnant from back in the days when each
drm driver had their own complete ioctl table, with no shared core
drm table at all.

To make really sure no mis-guided user in a kms driver pops up again
explicitly check for that in the new ioctl implementation.

v2: Drop the unused variable I've accidentally left in the code,
spotted by David Herrmann.

Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_bufs.c

@@ -1455,6 +1455,18 @@ int drm_mapbufs(struct drm_device *dev, void *data,
 	return retcode;
 }
 
+int drm_dma_ioctl(struct drm_device *dev, void *data,
+		  struct drm_file *file_priv)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	if (dev->driver->dma_ioctl)
+		return dev->driver->dma_ioctl(dev, data, file_priv);
+	else
+		return -EINVAL;
+}
+
 struct drm_local_map *drm_getsarea(struct drm_device *dev)
 {
 	struct drm_map_list *entry;

drivers/gpu/drm/drm_drv.c

@@ -106,8 +106,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_INFO_BUFS, drm_infobufs, DRM_AUTH),
 	DRM_IOCTL_DEF(DRM_IOCTL_MAP_BUFS, drm_mapbufs, DRM_AUTH),
 	DRM_IOCTL_DEF(DRM_IOCTL_FREE_BUFS, drm_freebufs, DRM_AUTH),
-	/* The DRM_IOCTL_DMA ioctl should be defined by the driver. */
-	DRM_IOCTL_DEF(DRM_IOCTL_DMA, NULL, DRM_AUTH),
+	DRM_IOCTL_DEF(DRM_IOCTL_DMA, drm_dma_ioctl, DRM_AUTH),
 
 	DRM_IOCTL_DEF(DRM_IOCTL_CONTROL, drm_control, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 
@@ -397,9 +396,6 @@ long drm_ioctl(struct file *filp,
 
 	/* Do not trust userspace, use our own definition */
 	func = ioctl->func;
-	/* is there a local override? */
-	if ((nr == DRM_IOCTL_NR(DRM_IOCTL_DMA)) && dev->driver->dma_ioctl)
-		func = dev->driver->dma_ioctl;
 
 	if (!func) {
 		DRM_DEBUG("no function\n");

include/drm/drmP.h

@@ -1355,6 +1355,8 @@ extern int drm_freebufs(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
 extern int drm_mapbufs(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv);
+extern int drm_dma_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *file_priv);
 
 				/* DMA support (drm_dma.h) */
 extern int drm_legacy_dma_setup(struct drm_device *dev);