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authorAmit Shah <amit.shah@redhat.com>2013-07-29 06:53:21 +0200
committerRusty Russell <rusty@rustcorp.com.au>2013-07-29 07:13:58 +0200
commit96f97a83910cdb9d89d127c5ee523f8fc040a804 (patch)
tree38578e6565dfd1e93ac3556b9c770d5fee37cc51
parentvirtio: console: fix raising SIGIO after port unplug (diff)
downloadlinux-96f97a83910cdb9d89d127c5ee523f8fc040a804.tar.xz
linux-96f97a83910cdb9d89d127c5ee523f8fc040a804.zip
virtio: console: return -ENODEV on all read operations after unplug
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. CC: <stable@vger.kernel.org> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--drivers/char/virtio_console.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e4845f1c9a0b..fc45567ad3ac 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;
/*