drm/atomic: -EACCESS for lease-denied crtc lookup

With the previous patch drm_crtc_find will return NULL when the crtc
isn't in our lease, which will then disable the plane/connector. No
longer an issue since the lessor can't escape their lease terms
anymore, but not quite great semantics yet either.

Catch this and return -EACCES, so that at least evil test cases have a
better chance of making sure the kernel works correctly.

Reviewed-by: Dave Airlie <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_atomic_uapi.c

···
 
 	} else if (property == config->prop_crtc_id) {
 		struct drm_crtc *crtc = drm_crtc_find(dev, file_priv, val);
+		if (val && !crtc)
+			return -EACCES;
 		return drm_atomic_set_crtc_for_plane(state, crtc);
 	} else if (property == config->prop_crtc_x) {
 		state->crtc_x = U642I64(val);
···
 
 	if (property == config->prop_crtc_id) {
 		struct drm_crtc *crtc = drm_crtc_find(dev, file_priv, val);
+		if (val && !crtc)
+			return -EACCES;
 		return drm_atomic_set_crtc_for_connector(state, crtc);
 	} else if (property == config->dpms_property) {
 		/* setting DPMS property requires special handling, which