staging: vc04_services: Handle conversion from VCHIQ_SERVICE_HANDLE_T to VCHI_SERVICE...

A VCHIQ_SERVICE_HANDLE_T which is an int is stuffed into a
VCHI_SERVICE_HANDLE_T which is a pointer, passed around, then
converted back to a VCHIQ_SERVICE_HANDLE_T. Since the data is
always actually a VCHIQ_SERVICE_HANDLE_T(int), never actually a
pointer, it is safe to simply cast the two back in forth.

Note that pointers are never stuffed into an int.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_shim.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_shim.c
index 8072ff613636121d50293693d0bd2aaf0b6e07b5..49f9d6a8f78d592c6a1bb9ed4f64df9c53308722 100644 (file)
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_shim.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_shim.c
@@ -400,8 +400,16 @@ EXPORT_SYMBOL(vchi_msg_queuev);
  ***********************************************************/
 int32_t vchi_held_msg_release(VCHI_HELD_MSG_T *message)
 {
-       vchiq_release_message((VCHIQ_SERVICE_HANDLE_T)message->service,
-               (VCHIQ_HEADER_T *)message->message);
+       /*
+        * Convert the service field pointer back to an
+        * VCHIQ_SERVICE_HANDLE_T which is an int.
+        * This pointer is opaque to everything except
+        * vchi_msg_hold which simply upcasted the int
+        * to a pointer.
+        */
+
+       vchiq_release_message((VCHIQ_SERVICE_HANDLE_T)(long)message->service,
+                             (VCHIQ_HEADER_T *)message->message);
 
        return 0;
 }
@@ -445,8 +453,16 @@ int32_t vchi_msg_hold(VCHI_SERVICE_HANDLE_T handle,
        *data = header->data;
        *msg_size = header->size;
 
+       /*
+        * upcast the VCHIQ_SERVICE_HANDLE_T which is an int
+        * to a pointer and stuff it in the held message.
+        * This pointer is opaque to everything except
+        * vchi_held_msg_release which simply downcasts it back
+        * to an int.
+        */
+
        message_handle->service =
-               (struct opaque_vchi_service_t *)service->handle;
+               (struct opaque_vchi_service_t *)(long)service->handle;
        message_handle->message = header;
 
        return 0;