[PATCH v2 1/2] vhost-user-blk: use different event handlers on initialization

[Denis Plotnikov <den-plotnikov@yandex-team.ru>]

It is useful to use different connect/disconnect event handlers
on device initialization and operation as seen from the further
commit fixing a bug on device initialization.

The patch refactor the code to make use of them: we don't rely any
more on the VM state for choosing how to cleanup the device, instead
we explicitly use the proper event handler dependping on whether
the device has been initialized.

Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
---
 hw/block/vhost-user-blk.c | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index b870a50e6b20..1af95ec6aae7 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -362,7 +362,18 @@ static void vhost_user_blk_disconnect(DeviceState *dev)
     vhost_dev_cleanup(&s->dev);
 }
 
-static void vhost_user_blk_event(void *opaque, QEMUChrEvent event);
+static void vhost_user_blk_event(void *opaque, QEMUChrEvent event,
+                                 bool realized);
+
+static void vhost_user_blk_event_realize(void *opaque, QEMUChrEvent event)
+{
+    vhost_user_blk_event(opaque, event, false);
+}
+
+static void vhost_user_blk_event_oper(void *opaque, QEMUChrEvent event)
+{
+    vhost_user_blk_event(opaque, event, true);
+}
 
 static void vhost_user_blk_chr_closed_bh(void *opaque)
 {
@@ -371,11 +382,12 @@ static void vhost_user_blk_chr_closed_bh(void *opaque)
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 
     vhost_user_blk_disconnect(dev);
-    qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
-            NULL, opaque, NULL, true);
+    qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL,
+            vhost_user_blk_event_oper, NULL, opaque, NULL, true);
 }
 
-static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
+static void vhost_user_blk_event(void *opaque, QEMUChrEvent event,
+                                 bool realized)
 {
     DeviceState *dev = opaque;
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -406,7 +418,7 @@ static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
          * TODO: maybe it is a good idea to make the same fix
          * for other vhost-user devices.
          */
-        if (runstate_is_running()) {
+        if (realized) {
             AioContext *ctx = qemu_get_current_aio_context();
 
             qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL,
@@ -473,8 +485,9 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
     s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
     s->connected = false;
 
-    qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL, vhost_user_blk_event,
-                             NULL, (void *)dev, NULL, true);
+    qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL,
+                             vhost_user_blk_event_realize, NULL, (void *)dev,
+                             NULL, true);
 
 reconnect:
     if (qemu_chr_fe_wait_connected(&s->chardev, &err) < 0) {
@@ -494,6 +507,10 @@ reconnect:
         goto reconnect;
     }
 
+    /* we're fully initialized, now we can operate, so change the handler */
+    qemu_chr_fe_set_handlers(&s->chardev,  NULL, NULL,
+                             vhost_user_blk_event_oper, NULL, (void *)dev,
+                             NULL, true);
     return;
 
 virtio_err:
-- 
2.25.1