usb: xhci: remove redundant update_ring_for_set_deq_completion() function

The function is a remnant from a previous implementation and is now
redundant. There is no longer a need to search for the dequeue pointer,
as both the TRB and segment dequeue pointers are saved within
'queued_deq_seg' and 'queued_deq_ptr'.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250306144954.3507700-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Epicurius

drivers/usb/host/xhci-ring.c

@@ -1332,43 +1332,6 @@ void xhci_hc_died(struct xhci_hcd *xhci)
 		usb_hc_died(xhci_to_hcd(xhci));
 }
 
-static void update_ring_for_set_deq_completion(struct xhci_hcd *xhci,
-		struct xhci_virt_device *dev,
-		struct xhci_ring *ep_ring,
-		unsigned int ep_index)
-{
-	union xhci_trb *dequeue_temp;
-
-	dequeue_temp = ep_ring->dequeue;
-
-	/* If we get two back-to-back stalls, and the first stalled transfer
-	 * ends just before a link TRB, the dequeue pointer will be left on
-	 * the link TRB by the code in the while loop.  So we have to update
-	 * the dequeue pointer one segment further, or we'll jump off
-	 * the segment into la-la-land.
-	 */
-	if (trb_is_link(ep_ring->dequeue)) {
-		ep_ring->deq_seg = ep_ring->deq_seg->next;
-		ep_ring->dequeue = ep_ring->deq_seg->trbs;
-	}
-
-	while (ep_ring->dequeue != dev->eps[ep_index].queued_deq_ptr) {
-		/* We have more usable TRBs */
-		ep_ring->dequeue++;
-		if (trb_is_link(ep_ring->dequeue)) {
-			if (ep_ring->dequeue ==
-					dev->eps[ep_index].queued_deq_ptr)
-				break;
-			ep_ring->deq_seg = ep_ring->deq_seg->next;
-			ep_ring->dequeue = ep_ring->deq_seg->trbs;
-		}
-		if (ep_ring->dequeue == dequeue_temp) {
-			xhci_dbg(xhci, "Unable to find new dequeue pointer\n");
-			break;
-		}
-	}
-}
-
 /*
  * When we get a completion for a Set Transfer Ring Dequeue Pointer command,
  * we need to clear the set deq pending flag in the endpoint ring state, so that
@@ -1473,8 +1436,8 @@ static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
 			/* Update the ring's dequeue segment and dequeue pointer
 			 * to reflect the new position.
 			 */
-			update_ring_for_set_deq_completion(xhci, ep->vdev,
-				ep_ring, ep_index);
+			ep_ring->deq_seg = ep->queued_deq_seg;
+			ep_ring->dequeue = ep->queued_deq_ptr;
 		} else {
 			xhci_warn(xhci, "Mismatch between completed Set TR Deq Ptr command & xHCI internal state.\n");
 			xhci_warn(xhci, "ep deq seg = %p, deq ptr = %p\n",