[PATCH] usbtest, add some unlink testcases

This adds some simple unlink test cases.  I've only run these
against OHCI so far, and so far only in simple configurations
(only one active device), where it hasn't yet turned up problems.

drivers/usb/misc/usbtest.c

@@ -550,6 +550,74 @@ static int ch9_postconfig (struct usbtest_dev *dev)
 
 /*-------------------------------------------------------------------------*/
 
+static void unlink1_callback (struct urb *urb)
+{
+	int	status = urb->status;
+
+	// we "know" -EPIPE (stall) never happens
+	if (!status)
+		status = usb_submit_urb (urb, SLAB_ATOMIC);
+	if (status) {
+		if (status == -ECONNRESET || status == -ENOENT)
+			status = 0;
+		urb->status = status;
+		complete ((struct completion *) urb->context);
+	}
+}
+
+static int unlink1 (struct usbtest_dev *dev, int pipe, int size, int async)
+{
+	struct urb		*urb;
+	struct completion	completion;
+	int			retval = 0;
+
+	init_completion (&completion);
+	urb = simple_alloc_urb (testdev_to_usbdev (dev), pipe, size);
+	if (async)
+		urb->transfer_flags |= URB_ASYNC_UNLINK;
+	urb->context = &completion;
+	urb->complete = unlink1_callback;
+
+	/* keep the endpoint busy.  there are lots of hc/hcd-internal
+	 * states, and testing should get to all of them over time.
+	 *
+	 * FIXME want additional tests for when endpoint is STALLing
+	 * due to errors, or is just NAKing requests.
+	 */
+	if ((retval = usb_submit_urb (urb, SLAB_KERNEL)) != 0) {
+		dbg ("submit/unlink fail %d", retval);
+		return retval;
+	}
+
+	/* unlinking that should always work.  variable delay tests more
+	 * hcd states and code paths, even with little other system load.
+	 */
+	wait_ms (jiffies % (2 * INTERRUPT_RATE));
+	retval = usb_unlink_urb (urb);
+	if (!(retval == 0 || retval == -EINPROGRESS)) {
+		dbg ("submit/unlink fail %d", retval);
+		return retval;
+	}
+
+	wait_for_completion (&completion);
+	retval = urb->status;
+	simple_free_urb (urb);
+	return retval;
+}
+
+static int unlink_simple (struct usbtest_dev *dev, int pipe, int len)
+{
+	int			retval = 0;
+
+	/* test sync and async paths */
+	retval = unlink1 (dev, pipe, len, 1);
+	if (!retval)
+		retval = unlink1 (dev, pipe, len, 0);
+	return retval;
+}
+
+/*-------------------------------------------------------------------------*/
+
 /* We only have this one interface to user space, through usbfs.
  * User mode code can scan usbfs to find N different devices (maybe on
  * different busses) to use when testing, and allocate one thread per
@@ -560,7 +628,8 @@ static int ch9_postconfig (struct usbtest_dev *dev)
  * video capture, and so on.  Run different tests at different times, in
  * different sequences.  Nothing here should interact with other devices,
  * except indirectly by consuming USB bandwidth and CPU resources for test
- * threads and request completion.
+ * threads and request completion.  But the only way to know that for sure
+ * is to test when HC queues are in use by many devices.
  */
 
 static int
@@ -761,13 +830,35 @@ usbtest_ioctl (struct usb_interface *intf, unsigned int code, void *buf)
 			dbg ("ch9 subset failed, iterations left %d", i);
 		break;
 
-	/* test cases for the unlink/cancel codepaths need a thread to
-	 * usb_unlink_urb() or usg_sg_cancel(), and a way to check if
-	 * the urb/sg_request was properly canceled.
-	 *
-	 * for the unlink-queued cases, the usb_sg_*() code uses/tests
-	 * the "streamed" cleanup mode, not the "packet" one
-	 */
+	// case 10: queued control
+
+	/* simple non-queued unlinks (ring with one urb) */
+	case 11:
+		if (dev->in_pipe == 0 || !param->length)
+			break;
+		retval = 0;
+		dbg ("%s TEST 11:  unlink %d reads of %d",
+				dev->id, param->iterations, param->length);
+		for (i = param->iterations; retval == 0 && i--; /* NOP */)
+			retval = unlink_simple (dev, dev->in_pipe, param->length);
+		if (retval)
+			dbg ("unlink reads failed, iterations left %d", i);
+		break;
+	case 12:
+		if (dev->out_pipe == 0 || !param->length)
+			break;
+		retval = 0;
+		dbg ("%s TEST 12:  unlink %d writes of %d",
+				dev->id, param->iterations, param->length);
+		for (i = param->iterations; retval == 0 && i--; /* NOP */)
+			retval = unlink_simple (dev, dev->out_pipe, param->length);
+		if (retval)
+			dbg ("unlink writes failed, iterations left %d", i);
+		break;
+
+	// FIXME unlink from queue (ring with N urbs)
+
+	// FIXME scatterlist cancel (needs helper thread)
 
 	}
 	do_gettimeofday (&param->duration);