3 files changed, 32 insertions, 8 deletions

diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index 5ccf984f063a..528429252f0f 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -98,6 +98,8 @@ struct ast_private {
 
 	struct drm_gem_object *cursor_cache;
 	uint64_t cursor_cache_gpu_addr;
+	/* Acces to this cache is protected by the crtc->mutex of the only crtc
+	 * we have. */
 	struct ttm_bo_kmap_obj cache_kmap;
 	int next_cursor;
 };
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index b7c6168fae7e..58fa69e5ff4c 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2036,7 +2036,6 @@ int drm_mode_cursor_ioctl(struct drm_device *dev,
 	if (!req->flags || (~DRM_MODE_CURSOR_FLAGS & req->flags))
 		return -EINVAL;
 
-	drm_modeset_lock_all(dev);
 	obj = drm_mode_object_find(dev, req->crtc_id, DRM_MODE_OBJECT_CRTC);
 	if (!obj) {
 		DRM_DEBUG_KMS("Unknown CRTC ID %d\n", req->crtc_id);
@@ -2051,20 +2050,23 @@ int drm_mode_cursor_ioctl(struct drm_device *dev,
 			goto out;
 		}
 		/* Turns off the cursor if handle is 0 */
+		mutex_lock(&crtc->mutex);
 		ret = crtc->funcs->cursor_set(crtc, file_priv, req->handle,
 					      req->width, req->height);
+		mutex_unlock(&crtc->mutex);
 	}
 
 	if (req->flags & DRM_MODE_CURSOR_MOVE) {
 		if (crtc->funcs->cursor_move) {
+			drm_modeset_lock_all(dev);
 			ret = crtc->funcs->cursor_move(crtc, req->x, req->y);
+			drm_modeset_unlock_all(dev);
 		} else {
 			ret = -EFAULT;
 			goto out;
 		}
 	}
 out:
-	drm_modeset_unlock_all(dev);
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 9c0876b908ae..8d82e631c305 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -180,16 +180,29 @@ int vmw_du_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
 	struct vmw_dma_buffer *dmabuf = NULL;
 	int ret;
 
+	/*
+	 * FIXME: Unclear whether there's any global state touched by the
+	 * cursor_set function, especially vmw_cursor_update_position looks
+	 * suspicious. For now take the easy route and reacquire all locks. We
+	 * can do this since the caller in the drm core doesn't check anything
+	 * which is protected by any looks.
+	 */
+	mutex_unlock(&crtc->mutex);
+	drm_modeset_lock_all(dev_priv->dev);
+
 	/* A lot of the code assumes this */
-	if (handle && (width != 64 || height != 64))
-		return -EINVAL;
+	if (handle && (width != 64 || height != 64)) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	if (handle) {
 		ret = vmw_user_lookup_handle(dev_priv, tfile,
 					     handle, &surface, &dmabuf);
 		if (ret) {
 			DRM_ERROR("failed to find surface or dmabuf: %i\n", ret);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto out;
 		}
 	}
 
@@ -197,7 +210,8 @@ int vmw_du_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
 	if (surface && !surface->snooper.image) {
 		DRM_ERROR("surface not suitable for cursor\n");
 		vmw_surface_unreference(&surface);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
 
 	/* takedown old cursor */
@@ -225,14 +239,20 @@ int vmw_du_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
 					       du->hotspot_x, du->hotspot_y);
 	} else {
 		vmw_cursor_update_position(dev_priv, false, 0, 0);
-		return 0;
+		ret = 0;
+		goto out;
 	}
 
 	vmw_cursor_update_position(dev_priv, true,
 				   du->cursor_x + du->hotspot_x,
 				   du->cursor_y + du->hotspot_y);
 
-	return 0;
+	ret = 0;
+out:
+	drm_modeset_unlock_all(dev_priv->dev);
+	mutex_lock(&crtc->mutex);
+
+	return ret;
 }
 
 int vmw_du_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)