qdev/qbus: remove failover specific code

Commit f3a850565693 ("qdev/qbus: add hidden device support") has
introduced a generic way to hide a device but it has modified
qdev_device_add() to check a specific option of the failover device,
"failover_pair_id", before calling the generic mechanism.

It's not needed (and not generic) to do that in qdev_device_add() because
this is also checked by the failover_hide_primary_device() function that
uses the generic mechanism to hide the device.

Cc: Jens Freimann <jfreimann@redhat.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20211019071532.682717-3-lvivier@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>

hw/net/virtio-net.c

@@ -3299,7 +3299,17 @@ static bool failover_hide_primary_device(DeviceListener *listener,
     if (!device_opts) {
         return false;
     }
-    standby_id = qdict_get_try_str(device_opts, "failover_pair_id");
+
+    if (!qdict_haskey(device_opts, "failover_pair_id")) {
+        return false;
+    }
+
+    if (!qdict_haskey(device_opts, "id")) {
+        error_setg(errp, "Device with failover_pair_id needs to have id");
+        return false;
+    }
+
+    standby_id = qdict_get_str(device_opts, "failover_pair_id");
     if (g_strcmp0(standby_id, n->netclient_name) != 0) {
         return false;
     }

softmmu/qdev-monitor.c

@@ -639,19 +639,13 @@ DeviceState *qdev_device_add_from_qdict(const QDict *opts,
         }
     }
 
-    if (qdict_haskey(opts, "failover_pair_id")) {
-        if (!qdict_haskey(opts, "id")) {
-            error_setg(errp, "Device with failover_pair_id don't have id");
-            return NULL;
-        }
-        if (qdev_should_hide_device(opts, from_json, errp)) {
-            if (bus && !qbus_is_hotpluggable(bus)) {
-                error_setg(errp, QERR_BUS_NO_HOTPLUG, bus->name);
-            }
-            return NULL;
-        } else if (*errp) {
-            return NULL;
+    if (qdev_should_hide_device(opts, from_json, errp)) {
+        if (bus && !qbus_is_hotpluggable(bus)) {
+            error_setg(errp, QERR_BUS_NO_HOTPLUG, bus->name);
         }
+        return NULL;
+    } else if (*errp) {
+        return NULL;
     }
 
     if (phase_check(PHASE_MACHINE_READY) && bus && !qbus_is_hotpluggable(bus)) {