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=-12.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 146D9C433E1 for ; Sun, 26 Jul 2020 11:05:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E72A92064B for ; Sun, 26 Jul 2020 11:05:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="WYkENyzY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727862AbgGZLFd (ORCPT ); Sun, 26 Jul 2020 07:05:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725972AbgGZLFc (ORCPT ); Sun, 26 Jul 2020 07:05:32 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80365C0619D2; Sun, 26 Jul 2020 04:05:31 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id s26so7594296pfm.4; Sun, 26 Jul 2020 04:05:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=HiCRrQCxdIa5HIW679AjRc9wXiJ6/iMtc+VYMoge+3c=; b=WYkENyzYNLhggQIvWLddjbWxCjYrMSbzqNPQL1fj6YeDJ/9qPZxc5cQQwyNHLyZIM/ FGCZ9jLTyq9WFfYDRg0E8vaLl0le0BdIJ14LYb2+DbnaHJV1UoWAXTcURJqo7n8C837A UlP3Rcv2MkXCbkjYNkwvi0vKnYAorDTChREz40/kYkvpaF8rvEEABaWVdEhpYCzMCFCy Qml69TMC14lB3pyB9RatZMP5mMEyL+JY+t9GodCEblfEf8rNTk4bFCFJv0LFLnUHQuAO pxjVfCsKTX2lM8rooNJj53HGkb1EaDKuaM5ardkNToiC64I5vBjEzx8nWDftzGytEXfC vPbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=HiCRrQCxdIa5HIW679AjRc9wXiJ6/iMtc+VYMoge+3c=; b=Q0UmFUwI8mE5Y+bk1A75MsUeKSBNRAD6sgS/Mu+bsrRAeexunt95hJw9HuHm1YEEHC cQmZ/r/7DS3aLMH/W4XkS4KHJH3rNbv6pho/k+Sb7O1XgLh1TZ/+eAW2MH0TC541dqFD uCD1/ksLmUpPp2jnPTmGrY3D9D5navrFo3J7Nx6vd1/jNNRJBmf/iEUo6dbnlvbrgszv bDW3xO4kykpsB0ZF0l3ozylsUHy5pYsQdxzIVnzCIcHQ41mF7jsEGjRq/rBGPWitEEKj O686lGAn2XdZv5iWQ+jOrkbO+GQhTuiUXpiVNtVLlTmYk1waA5ckLHDRqycGUT+y9wwo nG5g== X-Gm-Message-State: AOAM530J9qJtKfXeMQg23CPuctyGJ9aEYVYviU310i6GwZYCrvn6beIl koXX9w8P0F+Xl7sXR0lb75k= X-Google-Smtp-Source: ABdhPJyiB5VtWifib5GOY++GVorvqouyq8vwC0EJyVkpB+Ix4FfPXx8aOuJ9pPX9LeT7k3oVTaNAHA== X-Received: by 2002:a62:7712:: with SMTP id s18mr3235662pfc.65.1595761531090; Sun, 26 Jul 2020 04:05:31 -0700 (PDT) Received: from shane-XPS-13-9380.hsd1.ca.comcast.net ([2601:646:8880:9ae0:2977:21:5b62:ff11]) by smtp.gmail.com with ESMTPSA id q20sm12022374pfn.111.2020.07.26.04.05.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Jul 2020 04:05:30 -0700 (PDT) From: Xie He To: "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-x25@vger.kernel.org Cc: Xie He Subject: [PATCH] drivers/net/wan/lapbether: Use needed_headroom instead of hard_header_len Date: Sun, 26 Jul 2020 04:05:24 -0700 Message-Id: <20200726110524.151957-1-xie.he.0141@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In net/packet/af_packet.c, the function packet_snd first reserves a headroom of length (dev->hard_header_len + dev->needed_headroom). Then if the socket is a SOCK_DGRAM socket, it calls dev_hard_header, which calls dev->header_ops->create, to create the link layer header. If the socket is a SOCK_RAW socket, it "un-reserves" a headroom of length (dev->hard_header_len), and assumes the user to provide the appropriate link layer header. So according to the logic of af_packet.c, dev->hard_header_len should be the length of the header that would be created by dev->header_ops->create. However, this driver doesn't provide dev->header_ops, so logically dev->hard_header_len should be 0. So we should use dev->needed_headroom instead of dev->hard_header_len to request necessary headroom to be allocated. Signed-off-by: Xie He --- drivers/net/wan/lapbether.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c index b2868433718f..34cf6db89912 100644 --- a/drivers/net/wan/lapbether.c +++ b/drivers/net/wan/lapbether.c @@ -305,6 +305,7 @@ static void lapbeth_setup(struct net_device *dev) dev->netdev_ops = &lapbeth_netdev_ops; dev->needs_free_netdev = true; dev->type = ARPHRD_X25; + dev->hard_header_len = 0; dev->mtu = 1000; dev->addr_len = 0; } @@ -331,7 +332,8 @@ static int lapbeth_new_device(struct net_device *dev) * then this driver prepends a length field of 2 bytes, * then the underlying Ethernet device prepends its own header. */ - ndev->hard_header_len = -1 + 3 + 2 + dev->hard_header_len; + ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len + + dev->needed_headroom; lapbeth = netdev_priv(ndev); lapbeth->axdev = ndev; -- 2.25.1