USB: xHCI: handle_tx_event() refactor: finish_td

This patch moves the td universal processing part in handle_tx_event()
into a separate function finish_td().

if finish_td() returns 1, it indicates the urb can be given back.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/xhci-ring.c

@@ -1257,6 +1257,104 @@ int xhci_is_vendor_info_code(struct xhci_hcd *xhci, unsigned int trb_comp_code)
 	return 0;
 }
 
+/*
+ * Finish the td processing, remove the td from td list;
+ * Return 1 if the urb can be given back.
+ */
+static int finish_td(struct xhci_hcd *xhci, struct xhci_td *td,
+	union xhci_trb *event_trb, struct xhci_transfer_event *event,
+	struct xhci_virt_ep *ep, int *status, bool skip)
+{
+	struct xhci_virt_device *xdev;
+	struct xhci_ring *ep_ring;
+	unsigned int slot_id;
+	int ep_index;
+	struct urb *urb = NULL;
+	struct xhci_ep_ctx *ep_ctx;
+	int ret = 0;
+	u32 trb_comp_code;
+
+	slot_id = TRB_TO_SLOT_ID(event->flags);
+	xdev = xhci->devs[slot_id];
+	ep_index = TRB_TO_EP_ID(event->flags) - 1;
+	ep_ring = xhci_dma_to_transfer_ring(ep, event->buffer);
+	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
+	trb_comp_code = GET_COMP_CODE(event->transfer_len);
+
+	if (skip)
+		goto td_cleanup;
+
+	if (trb_comp_code == COMP_STOP_INVAL ||
+			trb_comp_code == COMP_STOP) {
+		/* The Endpoint Stop Command completion will take care of any
+		 * stopped TDs.  A stopped TD may be restarted, so don't update
+		 * the ring dequeue pointer or take this TD off any lists yet.
+		 */
+		ep->stopped_td = td;
+		ep->stopped_trb = event_trb;
+		return 0;
+	} else {
+		if (trb_comp_code == COMP_STALL) {
+			/* The transfer is completed from the driver's
+			 * perspective, but we need to issue a set dequeue
+			 * command for this stalled endpoint to move the dequeue
+			 * pointer past the TD.  We can't do that here because
+			 * the halt condition must be cleared first.  Let the
+			 * USB class driver clear the stall later.
+			 */
+			ep->stopped_td = td;
+			ep->stopped_trb = event_trb;
+			ep->stopped_stream = ep_ring->stream_id;
+		} else if (xhci_requires_manual_halt_cleanup(xhci,
+					ep_ctx, trb_comp_code)) {
+			/* Other types of errors halt the endpoint, but the
+			 * class driver doesn't call usb_reset_endpoint() unless
+			 * the error is -EPIPE.  Clear the halted status in the
+			 * xHCI hardware manually.
+			 */
+			xhci_cleanup_halted_endpoint(xhci,
+					slot_id, ep_index, ep_ring->stream_id,
+					td, event_trb);
+		} else {
+			/* Update ring dequeue pointer */
+			while (ep_ring->dequeue != td->last_trb)
+				inc_deq(xhci, ep_ring, false);
+			inc_deq(xhci, ep_ring, false);
+		}
+
+td_cleanup:
+		/* Clean up the endpoint's TD list */
+		urb = td->urb;
+
+		/* Do one last check of the actual transfer length.
+		 * If the host controller said we transferred more data than
+		 * the buffer length, urb->actual_length will be a very big
+		 * number (since it's unsigned).  Play it safe and say we didn't
+		 * transfer anything.
+		 */
+		if (urb->actual_length > urb->transfer_buffer_length) {
+			xhci_warn(xhci, "URB transfer length is wrong, "
+					"xHC issue? req. len = %u, "
+					"act. len = %u\n",
+					urb->transfer_buffer_length,
+					urb->actual_length);
+			urb->actual_length = 0;
+			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
+				*status = -EREMOTEIO;
+			else
+				*status = 0;
+		}
+		list_del(&td->td_list);
+		/* Was this TD slated to be cancelled but completed anyway? */
+		if (!list_empty(&td->cancelled_td_list))
+			list_del(&td->cancelled_td_list);
+
+		ret = 1;
+	}
+
+	return ret;
+}
+
 /*
  * If this function returns an error condition, it means it got a Transfer
  * event with a corrupted Slot ID, Endpoint ID, or TRB DMA address.
@@ -1278,6 +1376,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 	int status = -EINPROGRESS;
 	struct xhci_ep_ctx *ep_ctx;
 	u32 trb_comp_code;
+	int ret = 0;
 
 	xhci_dbg(xhci, "In %s\n", __func__);
 	slot_id = TRB_TO_SLOT_ID(event->flags);
@@ -1308,7 +1407,6 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 		xhci_dbg(xhci, "Event TRB with TRB type ID %u\n",
 				(unsigned int) (event->flags & TRB_TYPE_BITMASK)>>10);
 		xhci_print_trb_offsets(xhci, (union xhci_trb *) event);
-		urb = NULL;
 		goto cleanup;
 	}
 	xhci_dbg(xhci, "%s - getting list entry\n", __func__);
@@ -1379,7 +1477,6 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 			break;
 		}
 		xhci_warn(xhci, "ERROR Unknown event condition, HC probably busted\n");
-		urb = NULL;
 		goto cleanup;
 	}
 	/* Now update the urb's actual_length and give back to the core */
@@ -1427,7 +1524,10 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 
 			xhci_cleanup_halted_endpoint(xhci,
 					slot_id, ep_index, 0, td, event_trb);
-			goto td_cleanup;
+
+			ret = finish_td(xhci, td, event_trb, event, ep,
+					 &status, true);
+			goto cleanup;
 		}
 		/*
 		 * Did we transfer any data, despite the errors that might have
@@ -1456,7 +1556,6 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 						td->urb->transfer_buffer_length -
 						TRB_LEN(event->transfer_len);
 					xhci_dbg(xhci, "Waiting for status stage event\n");
-					urb = NULL;
 					goto cleanup;
 				}
 			}
@@ -1558,68 +1657,16 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 					TRB_LEN(event->transfer_len);
 		}
 	}
-	if (trb_comp_code == COMP_STOP_INVAL ||
-			trb_comp_code == COMP_STOP) {
-		/* The Endpoint Stop Command completion will take care of any
-		 * stopped TDs.  A stopped TD may be restarted, so don't update
-		 * the ring dequeue pointer or take this TD off any lists yet.
-		 */
-		ep->stopped_td = td;
-		ep->stopped_trb = event_trb;
-	} else {
-		if (trb_comp_code == COMP_STALL) {
-			/* The transfer is completed from the driver's
-			 * perspective, but we need to issue a set dequeue
-			 * command for this stalled endpoint to move the dequeue
-			 * pointer past the TD.  We can't do that here because
-			 * the halt condition must be cleared first.  Let the
-			 * USB class driver clear the stall later.
-			 */
-			ep->stopped_td = td;
-			ep->stopped_trb = event_trb;
-			ep->stopped_stream = ep_ring->stream_id;
-		} else if (xhci_requires_manual_halt_cleanup(xhci,
-					ep_ctx, trb_comp_code)) {
-			/* Other types of errors halt the endpoint, but the
-			 * class driver doesn't call usb_reset_endpoint() unless
-			 * the error is -EPIPE.  Clear the halted status in the
-			 * xHCI hardware manually.
-			 */
-			xhci_cleanup_halted_endpoint(xhci,
-					slot_id, ep_index, ep_ring->stream_id, td, event_trb);
-		} else {
-			/* Update ring dequeue pointer */
-			while (ep_ring->dequeue != td->last_trb)
-				inc_deq(xhci, ep_ring, false);
-			inc_deq(xhci, ep_ring, false);
-		}
 
-td_cleanup:
-		/* Clean up the endpoint's TD list */
-		urb = td->urb;
-		/* Do one last check of the actual transfer length.
-		 * If the host controller said we transferred more data than
-		 * the buffer length, urb->actual_length will be a very big
-		 * number (since it's unsigned).  Play it safe and say we didn't
-		 * transfer anything.
-		 */
-		if (urb->actual_length > urb->transfer_buffer_length) {
-			xhci_warn(xhci, "URB transfer length is wrong, "
-					"xHC issue? req. len = %u, "
-					"act. len = %u\n",
-					urb->transfer_buffer_length,
-					urb->actual_length);
-			urb->actual_length = 0;
-			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
-				status = -EREMOTEIO;
-			else
-				status = 0;
-		}
-		list_del(&td->td_list);
-		/* Was this TD slated to be cancelled but completed anyway? */
-		if (!list_empty(&td->cancelled_td_list))
-			list_del(&td->cancelled_td_list);
+	ret =  finish_td(xhci, td, event_trb, event, ep, &status, false);
 
+cleanup:
+	inc_deq(xhci, xhci->event_ring, true);
+	xhci_set_hc_event_deq(xhci);
+
+	/* FIXME for multi-TD URBs (who have buffers bigger than 64MB) */
+	if (ret) {
+		urb = td->urb;
 		/* Leave the TD around for the reset endpoint function to use
 		 * (but only if it's not a control endpoint, since we already
 		 * queued the Set TR dequeue pointer command for stalled
@@ -1627,17 +1674,9 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 		 */
 		if (usb_endpoint_xfer_control(&urb->ep->desc) ||
 			(trb_comp_code != COMP_STALL &&
-				trb_comp_code != COMP_BABBLE)) {
+				trb_comp_code != COMP_BABBLE))
 			kfree(td);
-		}
-		urb->hcpriv = NULL;
-	}
-cleanup:
-	inc_deq(xhci, xhci->event_ring, true);
-	xhci_set_hc_event_deq(xhci);
 
-	/* FIXME for multi-TD URBs (who have buffers bigger than 64MB) */
-	if (urb) {
 		usb_hcd_unlink_urb_from_ep(xhci_to_hcd(xhci), urb);
 		xhci_dbg(xhci, "Giveback URB %p, len = %d, status = %d\n",
 				urb, urb->actual_length, status);