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/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 102d928..b279670 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -203,7 +203,8 @@
 					struct nlm_lock *, int, struct nlm_cookie *);
 __be32		  nlmsvc_unlock(struct nlm_file *, struct nlm_lock *);
 __be32		  nlmsvc_testlock(struct svc_rqst *, struct nlm_file *,
-			struct nlm_lock *, struct nlm_lock *, struct nlm_cookie *);
+			struct nlm_host *, struct nlm_lock *,
+			struct nlm_lock *, struct nlm_cookie *);
 __be32		  nlmsvc_cancel_blocked(struct nlm_file *, struct nlm_lock *);
 unsigned long	  nlmsvc_retry_blocked(void);
 void		  nlmsvc_traverse_blocks(struct nlm_host *, struct nlm_file *,