drm: Check mode object lease status in all master ioctl paths [v4]

Attempts to modify un-leased objects are rejected with an error.
Information returned about unleased objects is modified to make them
appear unusable and/or disconnected.

Changes for v2 as suggested by Daniel Vetter <daniel.vetter@ffwll.ch>:

 * With the change in the __drm_mode_object_find API to pass the
   file_priv along, we can now centralize most of the lease-based
   access checks in that function.

 * A few places skip that API and require in-line checks.

Changes for v3 provided by Dave Airlie <airlied@redhat.com>

 * remove support for leasing encoders.
 * add support for leasing planes.

Changes for v4

 * Only call drm_lease_held if DRIVER_MODESET.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 919e78d..cda8bfa 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -122,10 +122,12 @@
 	count = 0;
 	crtc_id = u64_to_user_ptr(card_res->crtc_id_ptr);
 	drm_for_each_crtc(crtc, dev) {
-		if (count < card_res->count_crtcs &&
-		    put_user(crtc->base.id, crtc_id + count))
-			return -EFAULT;
-		count++;
+		if (drm_lease_held(file_priv, crtc->base.id)) {
+			if (count < card_res->count_crtcs &&
+			    put_user(crtc->base.id, crtc_id + count))
+				return -EFAULT;
+			count++;
+		}
 	}
 	card_res->count_crtcs = count;
 
@@ -143,12 +145,14 @@
 	count = 0;
 	connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
 	drm_for_each_connector_iter(connector, &conn_iter) {
-		if (count < card_res->count_connectors &&
-		    put_user(connector->base.id, connector_id + count)) {
-			drm_connector_list_iter_end(&conn_iter);
-			return -EFAULT;
+		if (drm_lease_held(file_priv, connector->base.id)) {
+			if (count < card_res->count_connectors &&
+			    put_user(connector->base.id, connector_id + count)) {
+				drm_connector_list_iter_end(&conn_iter);
+				return -EFAULT;
+			}
+			count++;
 		}
-		count++;
 	}
 	card_res->count_connectors = count;
 	drm_connector_list_iter_end(&conn_iter);