lockd: eliminate duplicate nlmsvc_lookup_host call from nlmsvc_testlock

nlmsvc_testlock calls nlmsvc_lookup_host to find a nlm_host struct. The
callers of this functions, however, call nlmsvc_retrieve_args or
nlm4svc_retrieve_args, which also return a nlm_host struct.

Change nlmsvc_testlock to take a host arg instead of calling
nlmsvc_lookup_host itself and change the callers to pass a pointer to
the nlm_host they've already found.

We take a reference to host in the place where nlmsvc_testlock()
previous did a new lookup, so the reference counting is unchanged from
before.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index fce3d70..e099f58 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -128,7 +128,7 @@
 		return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;
 
 	/* Now check for conflicting locks */
-	resp->status = cast_status(nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie));
+	resp->status = cast_status(nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock, &resp->cookie));
 	if (resp->status == nlm_drop_reply)
 		rc = rpc_drop_reply;
 	else