server: Change cancel_async to take an optional iosb and only_thread.
diff --git a/server/request.h b/server/request.h
index 4fc3bd6..a0efd2d 100644
--- a/server/request.h
+++ b/server/request.h
@@ -1351,7 +1351,9 @@
 C_ASSERT( FIELD_OFFSET(struct register_async_request, count) == 56 );
 C_ASSERT( sizeof(struct register_async_request) == 64 );
 C_ASSERT( FIELD_OFFSET(struct cancel_async_request, handle) == 12 );
-C_ASSERT( sizeof(struct cancel_async_request) == 16 );
+C_ASSERT( FIELD_OFFSET(struct cancel_async_request, iosb) == 16 );
+C_ASSERT( FIELD_OFFSET(struct cancel_async_request, only_thread) == 24 );
+C_ASSERT( sizeof(struct cancel_async_request) == 32 );
 C_ASSERT( FIELD_OFFSET(struct ioctl_request, code) == 12 );
 C_ASSERT( FIELD_OFFSET(struct ioctl_request, async) == 16 );
 C_ASSERT( FIELD_OFFSET(struct ioctl_request, blocking) == 56 );