svc: Move the authinfo cache to svc_xprt.

Move the authinfo cache to svc_xprt. This allows both the TCP and RDMA
transports to share this logic. A flag bit is used to determine if
auth information is to be cached or not. Previously, this code looked
at the transport protocol.

I've also changed the spin_lock/unlock logic so that a lock is not taken for
transports that are not caching auth info.

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/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 3e6a1c8..d2ac130 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -75,6 +75,9 @@
 	struct svc_xprt *xprt =
 		container_of(kref, struct svc_xprt, xpt_ref);
 	struct module *owner = xprt->xpt_class->xcl_owner;
+	if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)
+	    && xprt->xpt_auth_cache != NULL)
+		svcauth_unix_info_release(xprt->xpt_auth_cache);
 	xprt->xpt_ops->xpo_free(xprt);
 	module_put(owner);
 }
@@ -100,6 +103,7 @@
 	INIT_LIST_HEAD(&xprt->xpt_list);
 	INIT_LIST_HEAD(&xprt->xpt_ready);
 	mutex_init(&xprt->xpt_mutex);
+	spin_lock_init(&xprt->xpt_lock);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_init);