xhci: cleanup and refactor process_ctrl_td()

Refactor pricess_ctrl_tx() to make it more readable
No functional changes
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-ring.c

@@ -1932,6 +1932,8 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
 	int ep_index;
 	struct xhci_ep_ctx *ep_ctx;
 	u32 trb_comp_code;
+	u32 remaining, requested;
+	bool on_data_stage;
 
 	slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->flags));
 	xdev = xhci->devs[slot_id];
@@ -1939,89 +1941,74 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
 	ep_ring = xhci_dma_to_transfer_ring(ep, le64_to_cpu(event->buffer));
 	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
 	trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
+	requested = td->urb->transfer_buffer_length;
+	remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
+
+	/* not setup (dequeue), or status stage means we are at data stage */
+	on_data_stage = (event_trb != ep_ring->dequeue &&
+			 event_trb != td->last_trb);
 
 	switch (trb_comp_code) {
 	case COMP_SUCCESS:
-		if (event_trb == ep_ring->dequeue) {
-			xhci_warn(xhci, "WARN: Success on ctrl setup TRB "
-					"without IOC set??\n");
-			*status = -ESHUTDOWN;
-		} else if (event_trb != td->last_trb) {
-			xhci_warn(xhci, "WARN: Success on ctrl data TRB "
-					"without IOC set??\n");
+		if (event_trb != td->last_trb) {
+			xhci_warn(xhci, "WARN: Success on ctrl %s TRB without IOC set?\n",
+				  on_data_stage ? "data" : "setup");
 			*status = -ESHUTDOWN;
-		} else {
-			*status = 0;
+			break;
 		}
+		*status = 0;
 		break;
 	case COMP_SHORT_TX:
-			*status = 0;
+		*status = 0;
 		break;
 	case COMP_STOP_SHORT:
-		if (event_trb == ep_ring->dequeue || event_trb == td->last_trb)
-			xhci_warn(xhci, "WARN: Stopped Short Packet on ctrl setup or status TRB\n");
+		if (on_data_stage)
+			td->urb->actual_length = remaining;
 		else
-			td->urb->actual_length =
-				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
-
-		return finish_td(xhci, td, event_trb, event, ep, status, false);
+			xhci_warn(xhci, "WARN: Stopped Short Packet on ctrl setup or status TRB\n");
+		goto finish_td;
 	case COMP_STOP:
-		/* Did we stop at data stage? */
-		if (event_trb != ep_ring->dequeue && event_trb != td->last_trb)
-			td->urb->actual_length =
-				td->urb->transfer_buffer_length -
-				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
-		/* fall through */
+		if (on_data_stage)
+			td->urb->actual_length = requested - remaining;
+		goto finish_td;
 	case COMP_STOP_INVAL:
-		return finish_td(xhci, td, event_trb, event, ep, status, false);
+		goto finish_td;
 	default:
 		if (!xhci_requires_manual_halt_cleanup(xhci,
-					ep_ctx, trb_comp_code))
+						       ep_ctx, trb_comp_code))
 			break;
-		xhci_dbg(xhci, "TRB error code %u, "
-				"halted endpoint index = %u\n",
-				trb_comp_code, ep_index);
+		xhci_dbg(xhci, "TRB error %u, halted endpoint index = %u\n",
+			 trb_comp_code, ep_index);
 		/* else fall through */
 	case COMP_STALL:
 		/* Did we transfer part of the data (middle) phase? */
-		if (event_trb != ep_ring->dequeue &&
-				event_trb != td->last_trb)
-			td->urb->actual_length =
-				td->urb->transfer_buffer_length -
-				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
+		if (on_data_stage)
+			td->urb->actual_length = requested - remaining;
 		else if (!td->urb_length_set)
 			td->urb->actual_length = 0;
-
-		return finish_td(xhci, td, event_trb, event, ep, status, false);
+		goto finish_td;
 	}
+
+	/* stopped at setup stage, no data transferred */
+	if (event_trb == ep_ring->dequeue)
+		goto finish_td;
+
 	/*
-	 * Did we transfer any data, despite the errors that might have
-	 * happened?  I.e. did we get past the setup stage?
+	 * if on data stage then update the actual_length of the URB and flag it
+	 * as set, so it won't be overwritten in the event for the last TRB.
 	 */
-	if (event_trb != ep_ring->dequeue) {
-		/* The event was for the status stage */
-		if (event_trb == td->last_trb) {
-			if (!td->urb_length_set) {
-				td->urb->actual_length =
-					td->urb->transfer_buffer_length;
-			}
-		} else {
-			/*
-			 * Maybe the event was for the data stage? If so, update
-			 * already the actual_length of the URB and flag it as
-			 * set, so that it is not overwritten in the event for
-			 * the last TRB.
-			 */
-			td->urb_length_set = true;
-			td->urb->actual_length =
-				td->urb->transfer_buffer_length -
-				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
-			xhci_dbg(xhci, "Waiting for status "
-					"stage event\n");
-			return 0;
-		}
+	if (on_data_stage) {
+		td->urb_length_set = true;
+		td->urb->actual_length = requested - remaining;
+		xhci_dbg(xhci, "Waiting for status stage event\n");
+		return 0;
 	}
 
+	/* at status stage */
+	if (!td->urb_length_set)
+		td->urb->actual_length = requested;
+
+finish_td:
 	return finish_td(xhci, td, event_trb, event, ep, status, false);
 }