FAILED: patch "[PATCH] virtio_console: drop custom control queue cleanup" failed to apply to 4.9-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 61a8950c5c5708cf2068b29ffde94e454e528208 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Fri, 20 Apr 2018 20:49:04 +0300
Subject: [PATCH] virtio_console: drop custom control queue cleanup

We now cleanup all VQs on device removal - no need
to handle the control VQ specially.

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 26a66ffd943e..2d87ce555140 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1988,21 +1988,6 @@ static void remove_vqs(struct ports_device *portdev)
 	kfree(portdev->out_vqs);
 }
 
-static void remove_controlq_data(struct ports_device *portdev)
-{
-	struct port_buffer *buf;
-	unsigned int len;
-
-	if (!use_multiport(portdev))
-		return;
-
-	while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
-		free_buf(buf, true);
-
-	while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
-		free_buf(buf, true);
-}
-
 /*
  * Once we're further in boot, we get probed like any other virtio
  * device.
@@ -2163,7 +2148,6 @@ static void virtcons_remove(struct virtio_device *vdev)
 	 * have to just stop using the port, as the vqs are going
 	 * away.
 	 */
-	remove_controlq_data(portdev);
 	remove_vqs(portdev);
 	kfree(portdev);
 }
@@ -2208,7 +2192,6 @@ static int virtcons_freeze(struct virtio_device *vdev)
 	 */
 	if (use_multiport(portdev))
 		virtqueue_disable_cb(portdev->c_ivq);
-	remove_controlq_data(portdev);
 
 	list_for_each_entry(port, &portdev->ports, list) {
 		virtqueue_disable_cb(port->in_vq);