[PATCH 7/7] virtio: console: Return -EPIPE if port on the host isn't connected

[Amit Shah <amit.shah@redhat.com>]

The virtio-serial ports are like pipes, if there's no reader on the
other end, sending data might get it either ignored or the host might
return '0', which would make guests get -EAGAIN. Since we know the state
of the host port connection, it's appropriate to let the application
know that the other end isn't connected.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 drivers/char/virtio_console.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 55de0b5..4562964 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -411,6 +411,9 @@ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count)
 	ssize_t ret;
 	unsigned int len;
 
+	if (use_multiport(port->portdev) && !port->host_connected)
+		return -EPIPE;
+
 	out_vq = port->out_vq;
 
 	sg_init_one(sg, in_buf, in_count);
-- 
1.6.2.5