[PATCH 14/14] virtio: console: Reference counting portdev structs is not needed

Amit Shah
Thu, 02 Sep 2010 13:08:30 -0000

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 at redhat.com>
---
 drivers/char/virtio_console.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 1e00221..793817b 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1723,6 +1723,14 @@ 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;
--
1.7.2.2