qapi: Avoid use of 'data' member of QAPI unions

QAPI code generators currently create a 'void *data' member as
part of the anonymous union embedded in the C struct corresponding
to a QAPI union.  However, directly assigning to this member of
the union feels a bit fishy, when we can assign to another member
of the struct instead.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1457021813-10704-9-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

blockdev.c

@@ -1202,15 +1202,11 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
     }
 }
 
-static void blockdev_do_action(TransactionActionKind type, void *data,
-                               Error **errp)
+static void blockdev_do_action(TransactionAction *action, Error **errp)
 {
-    TransactionAction action;
     TransactionActionList list;
 
-    action.type = type;
-    action.u.data = data;
-    list.value = &action;
+    list.value = action;
     list.next = NULL;
     qmp_transaction(&list, false, NULL, errp);
 }
@@ -1236,8 +1232,11 @@ void qmp_blockdev_snapshot_sync(bool has_device, const char *device,
         .has_mode = has_mode,
         .mode = mode,
     };
-    blockdev_do_action(TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC,
-                       &snapshot, errp);
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC,
+        .u.blockdev_snapshot_sync = &snapshot,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 void qmp_blockdev_snapshot(const char *node, const char *overlay,
@@ -1247,9 +1246,11 @@ void qmp_blockdev_snapshot(const char *node, const char *overlay,
         .node = (char *) node,
         .overlay = (char *) overlay
     };
-
-    blockdev_do_action(TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT,
-                       &snapshot_data, errp);
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT,
+        .u.blockdev_snapshot = &snapshot_data,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 void qmp_blockdev_snapshot_internal_sync(const char *device,
@@ -1260,9 +1261,11 @@ void qmp_blockdev_snapshot_internal_sync(const char *device,
         .device = (char *) device,
         .name = (char *) name
     };
-
-    blockdev_do_action(TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC,
-                       &snapshot, errp);
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC,
+        .u.blockdev_snapshot_internal_sync = &snapshot,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,

ui/input.c

@@ -470,7 +470,7 @@ InputEvent *qemu_input_event_new_move(InputEventKind kind,
     InputMoveEvent *move = g_new0(InputMoveEvent, 1);
 
     evt->type = kind;
-    evt->u.data = move;
+    evt->u.rel = move; /* evt->u.rel is the same as evt->u.abs */
     move->axis = axis;
     move->value = value;
     return evt;