staging: line6: Pass *_process_message() `usb_line6' pointers

Casting the `struct usb_line6' pointer at the call point makes the code
difficult to read.  This is substantially cleaned up by moving the cast
into the callees.
Signed-off-by: Chris Rorvick <chris@rorvick.com>
Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

drivers/staging/line6/driver.c

@@ -544,8 +544,7 @@ static void line6_data_received(struct urb *urb)
 		case LINE6_PODXT:
 		case LINE6_PODXTPRO:
 		case LINE6_POCKETPOD:
-			line6_pod_process_message((struct usb_line6_pod *)
-						  line6);
+			line6_pod_process_message(line6);
 			break;
 
 		case LINE6_PODHD300:
@@ -555,19 +554,15 @@ static void line6_data_received(struct urb *urb)
 			break; /* let userspace handle MIDI */
 
 		case LINE6_PODXTLIVE_POD:
-			line6_pod_process_message((struct usb_line6_pod
-							   *)line6);
+			line6_pod_process_message(line6);
 			break;
 
 		case LINE6_PODXTLIVE_VARIAX:
-			line6_variax_process_message((struct
-						      usb_line6_variax
-						      *)line6);
+			line6_variax_process_message(line6);
 			break;
 
 		case LINE6_VARIAX:
-			line6_variax_process_message((struct usb_line6_variax *)
-						     line6);
+			line6_variax_process_message(line6);
 			break;
 
 		default:

drivers/staging/line6/pod.c

@@ -131,8 +131,9 @@ static char *pod_alloc_sysex_buffer(struct usb_line6_pod *pod, int code,
 /*
 	Process a completely received message.
 */
-void line6_pod_process_message(struct usb_line6_pod *pod)
+void line6_pod_process_message(struct usb_line6 *line6)
 {
+	struct usb_line6_pod *pod = (struct usb_line6_pod *) line6;
 	const unsigned char *buf = pod->line6.buffer_message;
 
 	if (memcmp(buf, pod_version_header, sizeof(pod_version_header)) == 0) {

drivers/staging/line6/pod.h

@@ -89,6 +89,6 @@ struct usb_line6_pod {
 extern void line6_pod_disconnect(struct usb_interface *interface);
 extern int line6_pod_init(struct usb_interface *interface,
 			  struct usb_line6 *line6);
-extern void line6_pod_process_message(struct usb_line6_pod *pod);
+extern void line6_pod_process_message(struct usb_line6 *line6);
 
 #endif

drivers/staging/line6/variax.c

@@ -130,8 +130,9 @@ static void variax_startup6(struct work_struct *work)
 /*
 	Process a completely received message.
 */
-void line6_variax_process_message(struct usb_line6_variax *variax)
+void line6_variax_process_message(struct usb_line6 *line6)
 {
+	struct usb_line6_variax *variax = (struct usb_line6_variax *) line6;
 	const unsigned char *buf = variax->line6.buffer_message;
 
 	switch (buf[0]) {

drivers/staging/line6/variax.h

@@ -67,6 +67,6 @@ struct usb_line6_variax {
 extern void line6_variax_disconnect(struct usb_interface *interface);
 extern int line6_variax_init(struct usb_interface *interface,
 			     struct usb_line6 *line6);
-extern void line6_variax_process_message(struct usb_line6_variax *variax);
+extern void line6_variax_process_message(struct usb_line6 *line6);
 
 #endif