virtio: console: Make write() return -ENODEV on hot-unplug

When a port is hot-unplugged while an app was blocked on a write() call,
the call was unblocked but would not get an error returned.

Return -ENODEV to ensure the app knows the port has gone away.

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

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e17ecf5d42b522d2df6bd3dc2e05f52d642d916c..70f1c38fa14cd959efdb534542ea6139b7d8e612 100644 (file)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -626,6 +626,9 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
                if (ret < 0)
                        return ret;
        }
+       /* Port got hot-unplugged. */
+       if (!port->guest_connected)
+               return -ENODEV;
 
        count = min((size_t)(32 * 1024), count);