xhci: handle failed buffer copy to URB sg list and fix a W=1 copiler warning

Set the urb->actual_length to bytes successfully copied in case all bytes
weren't copied from a temporary buffer to the URB sg list.
Also print a debug message
Signed-off-by: NMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210617150354.1512157-4-mathias.nyman@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci.c

@@ -1361,12 +1361,17 @@ static void xhci_unmap_temp_buf(struct usb_hcd *hcd, struct urb *urb)
 				 urb->transfer_buffer_length,
 				 dir);
 
-	if (usb_urb_dir_in(urb))
+	if (usb_urb_dir_in(urb)) {
 		len = sg_pcopy_from_buffer(urb->sg, urb->num_sgs,
 					   urb->transfer_buffer,
 					   buf_len,
 					   0);
-
+		if (len != buf_len) {
+			xhci_dbg(hcd_to_xhci(hcd),
+				 "Copy from tmp buf to urb sg list failed\n");
+			urb->actual_length = len;
+		}
+	}
 	urb->transfer_flags &= ~URB_DMA_MAP_SINGLE;
 	kfree(urb->transfer_buffer);
 	urb->transfer_buffer = NULL;