xhci: Set correct transferred length for cancelled bulk transfers

The transferred length is set incorrectly for cancelled bulk
transfer TDs in case the bulk transfer ring stops on the last transfer
block with a 'Stop - Length Invalid' completion code.

length essentially ends up being set to the requested length:
urb->actual_length = urb->transfer_buffer_length

Length for 'Stop - Length Invalid' cases should be the sum of all
TRB transfer block lengths up to the one the ring stopped on,
_excluding_ the one stopped on.

Fix this by always summing up TRB lengths for 'Stop - Length Invalid'
bulk cases.

This issue was discovered by Alan Stern while debugging
https://bugzilla.kernel.org/show_bug.cgi?id=218890, but does not
solve that bug. Issue is older than 4.10 kernel but fix won't apply
to those due to major reworks in that area.

Tested-by: Pierre Tomon <[email protected]>
Cc: [email protected] # v4.10+
Cc: Alan Stern <[email protected]>
Signed-off-by: Mathias Nyman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: matnyman

drivers/usb/host/xhci-ring.c

@@ -2524,9 +2524,8 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
 		goto finish_td;
 	case COMP_STOPPED_LENGTH_INVALID:
 		/* stopped on ep trb with invalid length, exclude it */
-		ep_trb_len	= 0;
-		remaining	= 0;
-		break;
+		td->urb->actual_length = sum_trb_lengths(xhci, ep_ring, ep_trb);
+		goto finish_td;
 	case COMP_USB_TRANSACTION_ERROR:
 		if (xhci->quirks & XHCI_NO_SOFT_RETRY ||
 		    (ep->err_count++ > MAX_SOFT_RETRY) ||