USB: usbtest fix endless loop in unlink tests.

In tests 11 and 12 if the URB completes with an error status (eg babble)
the asynchrous unlink entered an endless loop trying to unlink
a non resubmitted URB.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/usbtest.c

@@ -1072,23 +1072,34 @@ static int unlink1 (struct usbtest_dev *dev, int pipe, int size, int async)
 	 */
 	msleep (jiffies % (2 * INTERRUPT_RATE));
 	if (async) {
-retry:
-		retval = usb_unlink_urb (urb);
-		if (retval == -EBUSY || retval == -EIDRM) {
-			/* we can't unlink urbs while they're completing.
-			 * or if they've completed, and we haven't resubmitted.
-			 * "normal" drivers would prevent resubmission, but
-			 * since we're testing unlink paths, we can't.
-			 */
-			ERROR(dev,  "unlink retry\n");
-			goto retry;
+		while (!completion_done(&completion)) {
+			retval = usb_unlink_urb(urb);
+
+			switch (retval) {
+			case -EBUSY:
+			case -EIDRM:
+				/* we can't unlink urbs while they're completing
+				 * or if they've completed, and we haven't
+				 * resubmitted. "normal" drivers would prevent
+				 * resubmission, but since we're testing unlink
+				 * paths, we can't.
+				 */
+				ERROR(dev, "unlink retry\n");
+				continue;
+			case 0:
+			case -EINPROGRESS:
+				break;
+
+			default:
+				dev_err(&dev->intf->dev,
+					"unlink fail %d\n", retval);
+				return retval;
+			}
+
+			break;
 		}
 	} else
 		usb_kill_urb (urb);
-	if (!(retval == 0 || retval == -EINPROGRESS)) {
-		dev_err(&dev->intf->dev, "unlink fail %d\n", retval);
-		return retval;
-	}
 
 	wait_for_completion (&completion);
 	retval = urb->status;