virtio: console: Reference counting portdev structs is not needed

Explain in a comment why there's no need to reference-count the portdev
struct: when a device is yanked out, we can't do anything more with it
anyway so just give up doing anything more with the data or the vqs and
exit cleanly.

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

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 288701ccbf7a..c84486b3e43d 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1738,6 +1738,14 @@ static void virtcons_remove(struct virtio_device *vdev)
 
         unregister_chrdev(portdev->chr_major, "virtio-portsdev");
 
+        /*
+         * When yanking out a device, we immediately lose the
+         * (device-side) queues.  So there's no point in keeping the
+         * guest side around till we drop our final reference.  This
+         * also means that any ports which are in an open state will
+         * have to just stop using the port, as the vqs are going
+         * away.
+         */
         if (use_multiport(portdev)) {
                 struct port_buffer *buf;
                 unsigned int len;