qdev-monitor: make Error **errp const where it is appropriate

Mostly, Error ** is for returning error from the function, so the
callee sets it. However qbus_list_bus and qbus_list_dev get already
filled errp parameter. They don't change the pointer itself, only
change the internal state of referenced Error object. So we can make
it Error *const * errp, to stress the behavior. It will also help
coccinelle script (in future) to distinguish such cases from common
errp usage.

While there, rename the functions to
qbus_error_append_bus_list_hint(), qbus_error_append_dev_list_hint().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191205174635.18758-7-vsementsov@virtuozzo.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message replaced]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/qdev-monitor.c b/qdev-monitor.c
index 29ed73e..3465a1e 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -328,7 +328,8 @@ static Object *qdev_get_peripheral_anon(void)
     return dev;
 }
 
-static void qbus_list_bus(DeviceState *dev, Error **errp)
+static void qbus_error_append_bus_list_hint(DeviceState *dev,
+                                            Error *const *errp)
 {
     BusState *child;
     const char *sep = " ";
@@ -342,7 +343,8 @@ static void qbus_list_bus(DeviceState *dev, Error **errp)
     error_append_hint(errp, "\n");
 }
 
-static void qbus_list_dev(BusState *bus, Error **errp)
+static void qbus_error_append_dev_list_hint(BusState *bus,
+                                            Error *const *errp)
 {
     BusChild *kid;
     const char *sep = " ";
@@ -500,7 +502,7 @@ static BusState *qbus_find(const char *path, Error **errp)
         if (!dev) {
             error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
                       "Device '%s' not found", elem);
-            qbus_list_dev(bus, errp);
+            qbus_error_append_dev_list_hint(bus, errp);
             return NULL;
         }
 
@@ -518,7 +520,7 @@ static BusState *qbus_find(const char *path, Error **errp)
             if (dev->num_child_bus) {
                 error_setg(errp, "Device '%s' has multiple child buses",
                            elem);
-                qbus_list_bus(dev, errp);
+                qbus_error_append_bus_list_hint(dev, errp);
             } else {
                 error_setg(errp, "Device '%s' has no child bus", elem);
             }
@@ -534,7 +536,7 @@ static BusState *qbus_find(const char *path, Error **errp)
         bus = qbus_find_bus(dev, elem);
         if (!bus) {
             error_setg(errp, "Bus '%s' not found", elem);
-            qbus_list_bus(dev, errp);
+            qbus_error_append_bus_list_hint(dev, errp);
             return NULL;
         }
     }