SUNRPC: introduce svc helpers for prepairing rpcbind infrastructure

This helpers will be used only for those services, that will send portmapper
registration calls.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/clnt.h

@@ -136,6 +136,8 @@ void		rpc_shutdown_client(struct rpc_clnt *);
 void		rpc_release_client(struct rpc_clnt *);
 void		rpc_task_release_client(struct rpc_task *);
 
+int		rpcb_create_local(void);
+void		rpcb_put_local(void);
 int		rpcb_register(u32, u32, int, unsigned short);
 int		rpcb_v4_register(const u32 program, const u32 version,
 				 const struct sockaddr *address,

net/sunrpc/rpcb_clnt.c

@@ -320,7 +320,7 @@ out:
  * Returns zero on success, otherwise a negative errno value
  * is returned.
  */
-static int rpcb_create_local(void)
+int rpcb_create_local(void)
 {
 	static DEFINE_MUTEX(rpcb_create_local_mutex);
 	int result = 0;

net/sunrpc/svc.c

@@ -354,6 +354,41 @@ svc_pool_for_cpu(struct svc_serv *serv, int cpu)
 	return &serv->sv_pools[pidx % serv->sv_nrpools];
 }
 
+static int svc_rpcb_setup(struct svc_serv *serv)
+{
+	int err;
+
+	err = rpcb_create_local();
+	if (err)
+		return err;
+
+	/* Remove any stale portmap registrations */
+	svc_unregister(serv);
+	return 0;
+}
+
+static void svc_rpcb_cleanup(struct svc_serv *serv)
+{
+	svc_unregister(serv);
+	rpcb_put_local();
+}
+
+static int svc_uses_rpcbind(struct svc_serv *serv)
+{
+	struct svc_program	*progp;
+	unsigned int		i;
+
+	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
+		for (i = 0; i < progp->pg_nvers; i++) {
+			if (progp->pg_vers[i] == NULL)
+				continue;
+			if (progp->pg_vers[i]->vs_hidden == 0)
+				return 1;
+		}
+	}
+
+	return 0;
+}
 
 /*
  * Create an RPC service