drm: Make the prime vmap/vunmap hooks optional.

Some drivers leave these unimplemented, so don't make them have
unimplemented stubs.

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20180424004610.4637-2-eric@anholt.net
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index caf675e..397b46b 100644 (file)
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -409,7 +409,10 @@ void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
        struct drm_gem_object *obj = dma_buf->priv;
        struct drm_device *dev = obj->dev;
 
-       return dev->driver->gem_prime_vmap(obj);
+       if (dev->driver->gem_prime_vmap)
+               return dev->driver->gem_prime_vmap(obj);
+       else
+               return NULL;
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
 
@@ -426,7 +429,8 @@ void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
        struct drm_gem_object *obj = dma_buf->priv;
        struct drm_device *dev = obj->dev;
 
-       dev->driver->gem_prime_vunmap(obj, vaddr);
+       if (dev->driver->gem_prime_vunmap)
+               dev->driver->gem_prime_vunmap(obj, vaddr);
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);