xhci: simplify how we store TDs in urb private data

Instead of storing a zero length array of td pointers, and then
allocate memory both for the td pointer array and the td's, just
use a zero length array of actual td's in urb private data.

old:

struct urb_priv {
       struct xhci_td *td[0]
}

new:

struct urb_priv {
        struct xhci_td td[0]
}
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mem.c

@@ -1817,10 +1817,7 @@ struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
 
 void xhci_urb_free_priv(struct urb_priv *urb_priv)
 {
-	if (urb_priv) {
-		kfree(urb_priv->td[0]);
-		kfree(urb_priv);
-	}
+	kfree(urb_priv);
 }
 
 void xhci_free_command(struct xhci_hcd *xhci,

drivers/usb/host/xhci-ring.c

@@ -2838,7 +2838,7 @@ static int prepare_transfer(struct xhci_hcd *xhci,
 		return ret;
 
 	urb_priv = urb->hcpriv;
-	td = urb_priv->td[td_index];
+	td = &urb_priv->td[td_index];
 
 	INIT_LIST_HEAD(&td->td_list);
 	INIT_LIST_HEAD(&td->cancelled_td_list);
@@ -3134,7 +3134,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 	if (urb->transfer_flags & URB_ZERO_PACKET && urb_priv->num_tds > 1)
 		need_zero_pkt = true;
 
-	td = urb_priv->td[0];
+	td = &urb_priv->td[0];
 
 	/*
 	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
@@ -3227,7 +3227,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		ret = prepare_transfer(xhci, xhci->devs[slot_id],
 				       ep_index, urb->stream_id,
 				       1, urb, 1, mem_flags);
-		urb_priv->td[1]->last_trb = ring->enqueue;
+		urb_priv->td[1].last_trb = ring->enqueue;
 		field = TRB_TYPE(TRB_NORMAL) | ring->cycle_state | TRB_IOC;
 		queue_trb(xhci, ring, 0, 0, 0, TRB_INTR_TARGET(0), field);
 	}
@@ -3279,7 +3279,7 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		return ret;
 
 	urb_priv = urb->hcpriv;
-	td = urb_priv->td[0];
+	td = &urb_priv->td[0];
 
 	/*
 	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
@@ -3567,7 +3567,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 				return ret;
 			goto cleanup;
 		}
-		td = urb_priv->td[i];
+		td = &urb_priv->td[i];
 
 		/* use SIA as default, if frame id is used overwrite it */
 		sia_frame_id = TRB_SIA;
@@ -3674,20 +3674,20 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 	/* Clean up a partially enqueued isoc transfer. */
 
 	for (i--; i >= 0; i--)
-		list_del_init(&urb_priv->td[i]->td_list);
+		list_del_init(&urb_priv->td[i].td_list);
 
 	/* Use the first TD as a temporary variable to turn the TDs we've queued
 	 * into No-ops with a software-owned cycle bit. That way the hardware
 	 * won't accidentally start executing bogus TDs when we partially
 	 * overwrite them.  td->first_trb and td->start_seg are already set.
 	 */
-	urb_priv->td[0]->last_trb = ep_ring->enqueue;
+	urb_priv->td[0].last_trb = ep_ring->enqueue;
 	/* Every TRB except the first & last will have its cycle bit flipped. */
-	td_to_noop(xhci, ep_ring, urb_priv->td[0], true);
+	td_to_noop(xhci, ep_ring, &urb_priv->td[0], true);
 
 	/* Reset the ring enqueue back to the first TRB and its cycle bit. */
-	ep_ring->enqueue = urb_priv->td[0]->first_trb;
-	ep_ring->enq_seg = urb_priv->td[0]->start_seg;
+	ep_ring->enqueue = urb_priv->td[0].first_trb;
+	ep_ring->enq_seg = urb_priv->td[0].start_seg;
 	ep_ring->cycle_state = start_cycle;
 	ep_ring->num_trbs_free = ep_ring->num_trbs_free_temp;
 	usb_hcd_unlink_urb_from_ep(bus_to_hcd(urb->dev->bus), urb);

drivers/usb/host/xhci.c

@@ -1332,12 +1332,11 @@ static int xhci_check_maxpacket(struct xhci_hcd *xhci, unsigned int slot_id,
 int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	struct xhci_td *buffer;
 	unsigned long flags;
 	int ret = 0;
 	unsigned int slot_id, ep_index;
 	struct urb_priv	*urb_priv;
-	int num_tds, i;
+	int num_tds;
 
 	if (!urb || xhci_check_args(hcd, urb->dev, urb->ep,
 					true, true, __func__) <= 0)
@@ -1364,21 +1363,10 @@ int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
 		num_tds = 1;
 
 	urb_priv = kzalloc(sizeof(struct urb_priv) +
-			   num_tds * sizeof(struct xhci_td *), mem_flags);
+			   num_tds * sizeof(struct xhci_td), mem_flags);
 	if (!urb_priv)
 		return -ENOMEM;
 
-	buffer = kzalloc(num_tds * sizeof(struct xhci_td), mem_flags);
-	if (!buffer) {
-		kfree(urb_priv);
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < num_tds; i++) {
-		urb_priv->td[i] = buffer;
-		buffer++;
-	}
-
 	urb_priv->num_tds = num_tds;
 	urb_priv->num_tds_done = 0;
 	urb->hcpriv = urb_priv;
@@ -1526,7 +1514,7 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 		for (i = urb_priv->num_tds_done;
 		     i < urb_priv->num_tds && xhci->devs[urb->dev->slot_id];
 		     i++) {
-			td = urb_priv->td[i];
+			td = &urb_priv->td[i];
 			if (!list_empty(&td->td_list))
 				list_del_init(&td->td_list);
 			if (!list_empty(&td->cancelled_td_list))
@@ -1557,11 +1545,11 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 				urb, urb->dev->devpath,
 				urb->ep->desc.bEndpointAddress,
 				(unsigned long long) xhci_trb_virt_to_dma(
-					urb_priv->td[i]->start_seg,
-					urb_priv->td[i]->first_trb));
+					urb_priv->td[i].start_seg,
+					urb_priv->td[i].first_trb));
 
 	for (; i < urb_priv->num_tds; i++) {
-		td = urb_priv->td[i];
+		td = &urb_priv->td[i];
 		list_add_tail(&td->cancelled_td_list, &ep->cancelled_td_list);
 	}
 

drivers/usb/host/xhci.h

@@ -1610,7 +1610,7 @@ struct xhci_scratchpad {
 struct urb_priv {
 	int	num_tds;
 	int	num_tds_done;
-	struct	xhci_td	*td[0];
+	struct	xhci_td	td[0];
 };
 
 /*