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authorAmit Shah <amit.shah@redhat.com>2013-07-29 14:23:21 +0930
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-14 22:55:17 -0700
commit1336e0d81c7ea5128f87993907aaff3db71bf973 (patch)
treedc7db7247bdc4a32ec64db977f7a40201552e129
parent7ba6337874c92f15212065b120fa70de573c56ed (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>
-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 0d50d92b1019..f2fb2f2465e7 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -625,6 +625,10 @@ 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
@@ -641,7 +645,7 @@ 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;
/*