xen-kbdfront: handle backend CLOSED without CLOSING

Backend drivers shouldn't transistion to CLOSED unless the frontend is
CLOSED.  If a backend does transition to CLOSED too soon then the
frontend may not see the CLOSING state and will not properly shutdown.

So, treat an unexpected backend CLOSED state the same as CLOSING.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
index 02ca8680ea5b8f68393cecc3925792fc74236614..6f7d99013031b66f16d2c4e25f06dd3c352a622c 100644 (file)
--- a/drivers/input/misc/xen-kbdfront.c
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -311,7 +311,6 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
        case XenbusStateReconfiguring:
        case XenbusStateReconfigured:
        case XenbusStateUnknown:
-       case XenbusStateClosed:
                break;
 
        case XenbusStateInitWait:
@@ -350,6 +349,10 @@ InitWait:
 
                break;
 
+       case XenbusStateClosed:
+               if (dev->state == XenbusStateClosed)
+                       break;
+               /* Missed the backend's CLOSING state -- fallthrough */
        case XenbusStateClosing:
                xenbus_frontend_closed(dev);
                break;