nfsd/sunrpc: turn enqueueing a svc_xprt into a svc_serv operation

For now, all services use svc_xprt_do_enqueue, but once we add
workqueue-based service support, we'll need to do something different.

Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Shirley Ma <shirley.ma@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 0150003..97609d0 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -58,6 +58,9 @@
 	/* function for service threads to run */
 	int		(*svo_function)(void *);
 
+	/* queue up a transport for servicing */
+	void		(*svo_enqueue_xprt)(struct svc_xprt *);
+
 	/* optional module to count when adding threads (pooled svcs only) */
 	struct module	*svo_module;
 };