svc: Add per-transport delete functions

Add transport specific xpo_detach and xpo_free functions. The xpo_detach
function causes the transport to stop delivering data-ready events
and enqueing the transport for I/O.

The xpo_free function frees all resources associated with the particular
transport instance.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 01ee7bc..f032fb6 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -13,6 +13,8 @@
 	int		(*xpo_recvfrom)(struct svc_rqst *);
 	int		(*xpo_sendto)(struct svc_rqst *);
 	void		(*xpo_release_rqst)(struct svc_rqst *);
+	void		(*xpo_detach)(struct svc_xprt *);
+	void		(*xpo_free)(struct svc_xprt *);
 };
 
 struct svc_xprt_class {