usb: dwc3: gadget: increment request->actual once

BugLink: http://bugs.launchpad.net/bugs/1621113

commit c7de5734 upstream.

When using SG lists, we would end up setting
request->actual to:

	num_mapped_sgs * (request->length - count)

Let's fix that up by incrementing request->actual
only once.
Reported-by: Brian E Rogers <brian.e.rogers@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/usb/dwc3/gadget.c

@@ -1892,14 +1892,6 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 			s_pkt = 1;
 	}
 
-	/*
-	 * We assume here we will always receive the entire data block
-	 * which we should receive. Meaning, if we program RX to
-	 * receive 4K but we receive only 2K, we assume that's all we
-	 * should receive and we simply bounce the request back to the
-	 * gadget driver for further processing.
-	 */
-	req->request.actual += req->request.length - count;
 	if (s_pkt)
 		return 1;
 	if ((event->status & DEPEVT_STATUS_LST) &&
@@ -1919,6 +1911,7 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 	struct dwc3_trb		*trb;
 	unsigned int		slot;
 	unsigned int		i;
+	int			count = 0;
 	int			ret;
 
 	do {
@@ -1935,6 +1928,8 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 				slot++;
 			slot %= DWC3_TRB_NUM;
 			trb = &dep->trb_pool[slot];
+			count += trb->size & DWC3_TRB_SIZE_MASK;
+
 
 			ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
 					event, status);
@@ -1942,6 +1937,14 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 				break;
 		} while (++i < req->request.num_mapped_sgs);
 
+		/*
+		 * We assume here we will always receive the entire data block
+		 * which we should receive. Meaning, if we program RX to
+		 * receive 4K but we receive only 2K, we assume that's all we
+		 * should receive and we simply bounce the request back to the
+		 * gadget driver for further processing.
+		 */
+		req->request.actual += req->request.length - count;
 		dwc3_gadget_giveback(dep, req, status);
 
 		if (ret)