From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8CF0C04AB5 for ; Mon, 3 Jun 2019 19:43:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD189268D4 for ; Mon, 3 Jun 2019 19:43:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726722AbfFCTnw (ORCPT ); Mon, 3 Jun 2019 15:43:52 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:34118 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726157AbfFCTnv (ORCPT ); Mon, 3 Jun 2019 15:43:51 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 66D8414D06342; Mon, 3 Jun 2019 12:43:50 -0700 (PDT) Date: Mon, 03 Jun 2019 12:43:48 -0700 (PDT) Message-Id: <20190603.124348.5212561789204100.davem@davemloft.net> To: jwi@linux.ibm.com Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, ubraun@linux.ibm.com Subject: Re: [PATCH net 2/4] s390/qeth: don't use obsolete dst entry From: David Miller In-Reply-To: <20190603150446.23351-3-jwi@linux.ibm.com> References: <20190603150446.23351-1-jwi@linux.ibm.com> <20190603150446.23351-3-jwi@linux.ibm.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 03 Jun 2019 12:43:50 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Julian Wiedmann Date: Mon, 3 Jun 2019 17:04:44 +0200 > While qeth_l3 uses netif_keep_dst() to hold onto the dst, a skb's dst > may still have been obsoleted (via dst_dev_put()) by the time that we > end up using it. The dst then points to the loopback interface, which > means the neighbour lookup in qeth_l3_get_cast_type() determines a bogus > cast type of RTN_BROADCAST. > For IQD interfaces this causes us to place such skbs on the wrong > HW queue, resulting in TX errors. > > Fix-up the various call sites to check whether the dst is obsolete, and > fall back accordingly. > > Signed-off-by: Julian Wiedmann Please use "dst_check()". Some routes have DST_OBSOLETE_FORCE_CHK set on them from the very beginning so that uses of the route are forced through the dst->ops->check() method. Simply use dst_check() and then you can just retain the 'rt == NULL' logic as-is. Thanks.