[src/trunk]: src/sys/netinet Fix arplookup logic

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/36eb19301128
branches:  trunk
changeset: 340841:36eb19301128
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Mon Oct 05 08:17:31 2015 +0000

description:
Fix arplookup logic

It should first lookup and then create an entry if not found (and if
creation is requested).

diffstat:

 sys/netinet/if_arp.c |  14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

diffs (38 lines):

diff -r dbf1db67a3a6 -r 36eb19301128 sys/netinet/if_arp.c
--- a/sys/netinet/if_arp.c      Mon Oct 05 04:15:42 2015 +0000
+++ b/sys/netinet/if_arp.c      Mon Oct 05 08:17:31 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_arp.c,v 1.181 2015/09/11 10:33:32 roy Exp $ */
+/*     $NetBSD: if_arp.c,v 1.182 2015/10/05 08:17:31 ozaki-r Exp $     */
 
 /*-
  * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc.
@@ -68,7 +68,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.181 2015/09/11 10:33:32 roy Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.182 2015/10/05 08:17:31 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -1471,14 +1471,14 @@
                struct llentry *la;
                int flags = wlock ? LLE_EXCLUSIVE : 0;
 
-               if (create) {
+               IF_AFDATA_RLOCK(ifp);
+               la = lla_lookup(LLTABLE(ifp), flags, rt_getkey(rt));
+               IF_AFDATA_RUNLOCK(ifp);
+
+               if (la == NULL && create) {
                        IF_AFDATA_WLOCK(ifp);
                        la = lla_create(LLTABLE(ifp), flags, rt_getkey(rt));
                        IF_AFDATA_WUNLOCK(ifp);
-               } else {
-                       IF_AFDATA_RLOCK(ifp);
-                       la = lla_lookup(LLTABLE(ifp), flags, rt_getkey(rt));
-                       IF_AFDATA_RUNLOCK(ifp);
                }
 
                return la;