virtio: Add typedef for handle_output

The function pointer signature has been repeated a few times, using a
typedef may make coding easier.
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/virtio/virtio.c

@@ -95,8 +95,8 @@ struct VirtQueue
     int inuse;
 
     uint16_t vector;
-    void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
-    void (*handle_aio_output)(VirtIODevice *vdev, VirtQueue *vq);
+    VirtIOHandleOutput handle_output;
+    VirtIOHandleOutput handle_aio_output;
     VirtIODevice *vdev;
     EventNotifier guest_notifier;
     EventNotifier host_notifier;
@@ -1131,7 +1131,7 @@ void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
 }
 
 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
-                            void (*handle_output)(VirtIODevice *, VirtQueue *))
+                            VirtIOHandleOutput handle_output)
 {
     int i;
 
@@ -1804,8 +1804,7 @@ static void virtio_queue_host_notifier_aio_read(EventNotifier *n)
 }
 
 void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx,
-                                                void (*handle_output)(VirtIODevice *,
-                                                                      VirtQueue *))
+                                                VirtIOHandleOutput handle_output)
 {
     if (handle_output) {
         vq->handle_aio_output = handle_output;

include/hw/virtio/virtio.h

@@ -138,9 +138,10 @@ void virtio_cleanup(VirtIODevice *vdev);
 /* Set the child bus name. */
 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name);
 
+typedef void (*VirtIOHandleOutput)(VirtIODevice *, VirtQueue *);
+
 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
-                            void (*handle_output)(VirtIODevice *,
-                                                  VirtQueue *));
+                            VirtIOHandleOutput handle_output);
 
 void virtio_del_queue(VirtIODevice *vdev, int n);