virtio: console: don't rely on virtqueue_add_buf() returning capacity.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 8ab9c3d4bf13..89bdc31a3dc6 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -396,6 +396,8 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 
         ret = virtqueue_add_buf(vq, sg, 0, 1, buf, GFP_ATOMIC);
         virtqueue_kick(vq);
+        if (!ret)
+                ret = vq->num_free;
         return ret;
 }