USB: ldusb should signal an error in poll if the device is disconnected

poll() should test for a disconnection of the device.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/usb/misc/ldusb.c b/drivers/usb/misc/ldusb.c
index ad4fb15b5dcb..90f130126c10 100644
--- a/drivers/usb/misc/ldusb.c
+++ b/drivers/usb/misc/ldusb.c
@@ -412,6 +412,9 @@ static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
 
         dev = file->private_data;
 
+        if (!dev->intf)
+                return POLLERR | POLLHUP;
+
         poll_wait(file, &dev->read_wait, wait);
         poll_wait(file, &dev->write_wait, wait);
 
@@ -767,6 +770,9 @@ static void ld_usb_disconnect(struct usb_interface *intf)
                 ld_usb_delete(dev);
         } else {
                 dev->intf = NULL;
+                /* wake up pollers */
+                wake_up_interruptible_all(&dev->read_wait);
+                wake_up_interruptible_all(&dev->write_wait);
                 mutex_unlock(&dev->mutex);
         }