usb: gadget: add usb_endpoint_descriptor to struct usb_ep

Change usb_ep_enable() prototype to use endpoint
descriptor from usb_ep.

This optimization spares the FDs from saving the
endpoint chosen descriptor. This optimization is
not full though. To fully exploit this change, one
needs to update all the UDCs as well since in the
current implementation each of them saves the
endpoint descriptor in it's internal (and extended)
endpoint structure.

Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/gadget/printer.c b/drivers/usb/gadget/printer.c
index 271ef94..00e5f19 100644
--- a/drivers/usb/gadget/printer.c
+++ b/drivers/usb/gadget/printer.c
@@ -89,8 +89,7 @@
 	u8			config;
 	s8			interface;
 	struct usb_ep		*in_ep, *out_ep;
-	const struct usb_endpoint_descriptor
-				*in, *out;
+
 	struct list_head	rx_reqs;	/* List of free RX structs */
 	struct list_head	rx_reqs_active;	/* List of Active RX xfers */
 	struct list_head	rx_buffers;	/* List of completed xfers */
@@ -895,19 +894,20 @@
 {
 	int			result = 0;
 
-	dev->in = ep_desc(dev->gadget, &hs_ep_in_desc, &fs_ep_in_desc);
+	dev->in_ep->desc = ep_desc(dev->gadget, &hs_ep_in_desc, &fs_ep_in_desc);
 	dev->in_ep->driver_data = dev;
 
-	dev->out = ep_desc(dev->gadget, &hs_ep_out_desc, &fs_ep_out_desc);
+	dev->out_ep->desc = ep_desc(dev->gadget, &hs_ep_out_desc,
+				    &fs_ep_out_desc);
 	dev->out_ep->driver_data = dev;
 
-	result = usb_ep_enable(dev->in_ep, dev->in);
+	result = usb_ep_enable(dev->in_ep);
 	if (result != 0) {
 		DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
 		goto done;
 	}
 
-	result = usb_ep_enable(dev->out_ep, dev->out);
+	result = usb_ep_enable(dev->out_ep);
 	if (result != 0) {
 		DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
 		goto done;
@@ -918,8 +918,8 @@
 	if (result != 0) {
 		(void) usb_ep_disable(dev->in_ep);
 		(void) usb_ep_disable(dev->out_ep);
-		dev->in = NULL;
-		dev->out = NULL;
+		dev->in_ep->desc = NULL;
+		dev->out_ep->desc = NULL;
 	}
 
 	/* caller is responsible for cleanup on error */
@@ -933,12 +933,14 @@
 
 	DBG(dev, "%s\n", __func__);
 
-	if (dev->in)
+	if (dev->in_ep->desc)
 		usb_ep_disable(dev->in_ep);
 
-	if (dev->out)
+	if (dev->out_ep->desc)
 		usb_ep_disable(dev->out_ep);
 
+	dev->in_ep->desc = NULL;
+	dev->out_ep->desc = NULL;
 	dev->interface = -1;
 }
 
@@ -1104,9 +1106,9 @@
 		list_add(&req->list, &dev->tx_reqs);
 	}
 
-	if (usb_ep_enable(dev->in_ep, dev->in))
+	if (usb_ep_enable(dev->in_ep))
 		DBG(dev, "Failed to enable USB in_ep\n");
-	if (usb_ep_enable(dev->out_ep, dev->out))
+	if (usb_ep_enable(dev->out_ep))
 		DBG(dev, "Failed to enable USB out_ep\n");
 
 	wake_up_interruptible(&dev->rx_wait);