greybus: stash hd as context for all URBs

This changes the context value stashed with each USB URB so that it
is always the host device pointer.

In cport_out_callback() this allows us to get away with *not*
requiring the gbuf for handling completions any more.  We are
(currently) ignoring the gbuf status value returned anyway, so
we'll skip setting it altogether.

Greg's comments in cport_out_callback() point out that ignoring
this was misguided, and handling send errors will be put in
place in an upcoming patch.

The context is set to the host device pointer for SVC receive and
CPort receive URBs for consistency--because we can.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/es1-ap-usb.c

@@ -221,7 +221,7 @@ static int submit_gbuf(struct gbuf *gbuf, gfp_t gfp_mask)
 	usb_fill_bulk_urb(urb, udev,
 			  usb_sndbulkpipe(udev, es1->cport_out_endpoint),
 			  buffer, gbuf->transfer_buffer_length + 1,
-			  cport_out_callback, gbuf);
+			  cport_out_callback, hd);
 	retval = usb_submit_urb(urb, gfp_mask);
 	return retval;
 }
@@ -320,7 +320,8 @@ static void ap_disconnect(struct usb_interface *interface)
 /* Callback for when we get a SVC message */
 static void svc_in_callback(struct urb *urb)
 {
-	struct es1_ap_dev *es1 = urb->context;
+	struct greybus_host_device *hd = urb->context;
+	struct es1_ap_dev *es1 = hd_to_es1(hd);
 	struct device *dev = &urb->dev->dev;
 	int status = check_urb_status(urb);
 	int retval;
@@ -346,8 +347,9 @@ static void svc_in_callback(struct urb *urb)
 
 static void cport_in_callback(struct urb *urb)
 {
+	struct greybus_host_device *hd = urb->context;
+	struct es1_ap_dev *es1 = hd_to_es1(hd);
 	struct device *dev = &urb->dev->dev;
-	struct es1_ap_dev *es1 = urb->context;
 	int status = check_urb_status(urb);
 	int retval;
 	u8 cport;
@@ -387,15 +389,12 @@ static void cport_in_callback(struct urb *urb)
 
 static void cport_out_callback(struct urb *urb)
 {
-	struct gbuf *gbuf = urb->context;
-	struct es1_ap_dev *es1 = hd_to_es1(gbuf->hd);
+	struct greybus_host_device *hd = urb->context;
+	struct es1_ap_dev *es1 = hd_to_es1(hd);
 	unsigned long flags;
+	/* int status = check_urb_status(urb); */
 	int i;
 
-	/* Record whether the transfer was successful */
-	gbuf->status = check_urb_status(urb);
-	gbuf->hcd_data = NULL;
-
 	/*
 	 * See if this was an urb in our pool, if so mark it "free", otherwise
 	 * we need to free it ourselves.
@@ -414,6 +413,8 @@ static void cport_out_callback(struct urb *urb)
 	usb_free_urb(urb);
 
 	/*
+	 * Rest assured Greg, this craziness is getting fixed.
+	 *
 	 * Yes, you are right, we aren't telling anyone that the urb finished.
 	 * "That's crazy!  How does this all even work?" you might be saying.
 	 * The "magic" is the idea that greybus works on the "operation" level,
@@ -520,7 +521,7 @@ static int ap_probe(struct usb_interface *interface,
 	usb_fill_int_urb(es1->svc_urb, udev,
 			 usb_rcvintpipe(udev, es1->svc_endpoint),
 			 es1->svc_buffer, ES1_SVC_MSG_SIZE, svc_in_callback,
-			 es1, svc_interval);
+			 hd, svc_interval);
 	retval = usb_submit_urb(es1->svc_urb, GFP_KERNEL);
 	if (retval)
 		goto error;
@@ -540,7 +541,7 @@ static int ap_probe(struct usb_interface *interface,
 		usb_fill_bulk_urb(urb, udev,
 				  usb_rcvbulkpipe(udev, es1->cport_in_endpoint),
 				  buffer, ES1_GBUF_MSG_SIZE, cport_in_callback,
-				  es1);
+				  hd);
 		es1->cport_in_urb[i] = urb;
 		es1->cport_in_buffer[i] = buffer;
 		retval = usb_submit_urb(urb, GFP_KERNEL);