[Qemu-devel] [PATCH 3/8] virtio-serial: Discard unconsumed data before sending port close event

[Amit Shah]

The guest kernel can reclaim the buffers when it receives the port close
event or when a port is being removed. Ensure we free up the buffers
before we send out any events to the guest.

Signed-off-by: Amit Shah <address@hidden>
---
 hw/virtio-serial-bus.c |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 8d77c94..c0044b3 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -186,14 +186,15 @@ int virtio_serial_open(VirtIOSerialPort *port)
 int virtio_serial_close(VirtIOSerialPort *port)
 {
     port->host_connected = false;
-    send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
-
     /*
      * If there's any data the guest sent which the app didn't
      * consume, reset the throttling flag and discard the data.
      */
     port->throttled = false;
     flush_queued_data(port, true);
+
+    send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
+
     return 0;
 }
 
@@ -631,13 +632,17 @@ static void add_port(VirtIOSerial *vser, uint32_t port_id)
 
 static void remove_port(VirtIOSerial *vser, uint32_t port_id)
 {
+    VirtIOSerialPort *port;
     unsigned int i;
 
     i = port_id / 32;
     vser->ports_map[i] &= ~(1U << (port_id % 32));
 
-    send_control_event(find_port_by_id(vser, port_id),
-                       VIRTIO_CONSOLE_PORT_REMOVE, 1);
+    port = find_port_by_id(vser, port_id);
+    /* Flush out any unconsumed buffers first */
+    flush_queued_data(port, true);
+
+    send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
 }
 
 static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
-- 
1.6.2.5