diff options
authorAmit Shah <amit.shah@redhat.com>2013-07-29 14:23:21 +0930
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-14 22:59:09 -0700
commit61ffac73366844578d7e773cdc33a4f6adca09d3 (patch)
parent2817b99f91475b84c23cd353741ea485564f4562 (diff)
virtio: console: return -ENODEV on all read operations after unplug
commit 96f97a83910cdb9d89d127c5ee523f8fc040a804 upstream. If a port gets unplugged while a user is blocked on read(), -ENODEV is returned. However, subsequent read()s returned 0, indicating there's no host-side connection (but not indicating the device went away). This also happened when a port was unplugged and the user didn't have any blocking operation pending. If the user didn't monitor the SIGIO signal, they won't have a chance to find out if the port went away. Fix by returning -ENODEV on all read()s after the port gets unplugged. write() already behaves this way. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e4845f1c9a0..fc45567ad3a 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -749,6 +749,10 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
port = filp->private_data;
+ /* Port is hot-unplugged. */
+ if (!port->guest_connected)
+ return -ENODEV;
if (!port_has_data(port)) {
* If nothing's connected on the host just return 0 in
@@ -765,7 +769,7 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
if (ret < 0)
return ret;
- /* Port got hot-unplugged. */
+ /* Port got hot-unplugged while we were waiting above. */
if (!port->guest_connected)
return -ENODEV;