xHCI: refine td allocation

In xhci_urb_enqueue(), allocate a block of memory for all the TDs instead
of allocating memory for each of them separately. This reduces the number
of kzalloc calling when an isochronous usb is submitted.
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-mem.c

@@ -1666,18 +1666,10 @@ struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
 
 void xhci_urb_free_priv(struct xhci_hcd *xhci, struct urb_priv *urb_priv)
 {
-	int last;
-
-	if (!urb_priv)
-		return;
-
-	last = urb_priv->length - 1;
-	if (last >= 0) {
-		int	i;
-		for (i = 0; i <= last; i++)
-			kfree(urb_priv->td[i]);
-	}
+	if (urb_priv) {
+		kfree(urb_priv->td[0]);
 		kfree(urb_priv);
+	}
 }
 
 void xhci_free_command(struct xhci_hcd *xhci,

drivers/usb/host/xhci.c

@@ -1035,6 +1035,7 @@ 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;
@@ -1065,13 +1066,15 @@ int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
 	if (!urb_priv)
 		return -ENOMEM;
 
-	for (i = 0; i < size; i++) {
-		urb_priv->td[i] = kzalloc(sizeof(struct xhci_td), mem_flags);
-		if (!urb_priv->td[i]) {
-			urb_priv->length = i;
-			xhci_urb_free_priv(xhci, urb_priv);
+	buffer = kzalloc(size * sizeof(struct xhci_td), mem_flags);
+	if (!buffer) {
+		kfree(urb_priv);
 		return -ENOMEM;
 	}
+
+	for (i = 0; i < size; i++) {
+		urb_priv->td[i] = buffer;
+		buffer++;
 	}
 
 	urb_priv->length = size;