SUNRPC: Remove rpc_protocol()

Since nfs4_create_referral_server was the only call site of
rpc_protocol, rpc_protocol can now be removed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

include/linux/sunrpc/clnt.h

@@ -179,7 +179,6 @@ struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred,
 int		rpc_restart_call_prepare(struct rpc_task *);
 int		rpc_restart_call(struct rpc_task *);
 void		rpc_setbufsize(struct rpc_clnt *, unsigned int, unsigned int);
-int		rpc_protocol(struct rpc_clnt *);
 struct net *	rpc_net_ns(struct rpc_clnt *);
 size_t		rpc_max_payload(struct rpc_clnt *);
 size_t		rpc_max_bc_payload(struct rpc_clnt *);

net/sunrpc/clnt.c

@@ -1375,22 +1375,6 @@ rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize
 }
 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 
-/**
- * rpc_protocol - Get transport protocol number for an RPC client
- * @clnt: RPC client to query
- *
- */
-int rpc_protocol(struct rpc_clnt *clnt)
-{
-	int protocol;
-
-	rcu_read_lock();
-	protocol = rcu_dereference(clnt->cl_xprt)->prot;
-	rcu_read_unlock();
-	return protocol;
-}
-EXPORT_SYMBOL_GPL(rpc_protocol);
-
 /**
  * rpc_net_ns - Get the network namespace for this RPC client
  * @clnt: RPC client to query