SUNRPC: Replace clnt->cl_principal

The clnt->cl_principal is being used exclusively to store the service
target name for RPCSEC_GSS/krb5 callbacks. Replace it with something that
is stored only in the RPCSEC_GSS-specific code.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index 0dd00f4..a9ab577 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -87,6 +87,11 @@
 	/* per-flavor data */
 };
 
+struct rpc_auth_create_args {
+	rpc_authflavor_t pseudoflavor;
+	const char *target_name;
+};
+
 /* Flags for rpcauth_lookupcred() */
 #define RPCAUTH_LOOKUP_NEW		0x01	/* Accept an uninitialised cred */
 
@@ -97,7 +102,7 @@
 	struct module		*owner;
 	rpc_authflavor_t	au_flavor;	/* flavor (RPC_AUTH_*) */
 	char *			au_name;
-	struct rpc_auth *	(*create)(struct rpc_clnt *, rpc_authflavor_t);
+	struct rpc_auth *	(*create)(struct rpc_auth_create_args *, struct rpc_clnt *);
 	void			(*destroy)(struct rpc_auth *);
 
 	struct rpc_cred *	(*lookup_cred)(struct rpc_auth *, struct auth_cred *, int);
@@ -140,7 +145,8 @@
 struct rpc_cred *	rpc_lookup_machine_cred(const char *service_name);
 int			rpcauth_register(const struct rpc_authops *);
 int			rpcauth_unregister(const struct rpc_authops *);
-struct rpc_auth *	rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);
+struct rpc_auth *	rpcauth_create(struct rpc_auth_create_args *,
+				struct rpc_clnt *);
 void			rpcauth_release(struct rpc_auth *);
 rpc_authflavor_t	rpcauth_get_pseudoflavor(rpc_authflavor_t,
 				struct rpcsec_gss_info *);