virtio: console: fix raising SIGIO after port unplug

SIGIO should be sent when a port gets unplugged.  It should only be sent
to prcesses that have the port opened, and have asked for SIGIO to be
delivered.  We were clearing out guest_connected before calling
send_sigio_to_port(), resulting in a sigio not getting sent to
processes.

Fix by setting guest_connected to false after invoking the sigio
function.

CC: <stable@vger.kernel.org>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 4e684faee10b..e4845f1c9a0b 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1551,12 +1551,14 @@ static void unplug_port(struct port *port)
         spin_unlock_irq(&port->portdev->ports_lock);
 
         if (port->guest_connected) {
+                /* Let the app know the port is going down. */
+                send_sigio_to_port(port);
+
+                /* Do this after sigio is actually sent */
                 port->guest_connected = false;
                 port->host_connected = false;
-                wake_up_interruptible(&port->waitqueue);
 
-                /* Let the app know the port is going down. */
-                send_sigio_to_port(port);
+                wake_up_interruptible(&port->waitqueue);
         }
 
         if (is_console_port(port)) {