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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 A50B2C433E4 for ; Sun, 9 Aug 2020 17:11:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 804E1206B5 for ; Sun, 9 Aug 2020 17:11:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oBLCXUjl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726344AbgHIRLw (ORCPT ); Sun, 9 Aug 2020 13:11:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbgHIRLw (ORCPT ); Sun, 9 Aug 2020 13:11:52 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9669C061756; Sun, 9 Aug 2020 10:11:51 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id d19so3598517pgl.10; Sun, 09 Aug 2020 10:11:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mgOLBezWt79zIQjvAdBmYqr2eyqE9EwffvrtOtN04PU=; b=oBLCXUjlfrw4Fre6KD2wOrQhSVwagOpit8lWuYFs+toIXiUArJWCy86Re6GKyRN6BY 97PeSSdm39pOiofcF7ufAjWYkjLXxjTARF5pAjRPRE3dyo5ZUwOu4W5zt7nBazPcHJj+ JVkVGvtc5r0Rn+qCg6pONe+gjA0XH/gKEoOWqmjjE4HoJ+V3HaZKe4shnUSEQpnDpAKz U/v8rZ/Vz7nLgX3lsvyFhGQVgd6x/Hzw38qjqYj8kF4jhHsaPlZqT6rvPTAFu2yTOqH4 fZK5HD9vFCbrBw2nczI9YgZbbtHtzVfpwrs2NNGDRHsbEBKoQKyRAgs8zZbZk8fYa68O TqiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mgOLBezWt79zIQjvAdBmYqr2eyqE9EwffvrtOtN04PU=; b=BvPrXew93w8bftw9MkUxKayh1g/2wsJiSoVOpdyCX/rBSFjFNldRTvYuPPF9FBJLOC ic3MRXI5bBLpLGlMCbUEBEH681rTmYwubMpXD/QbzS8/kVmQ3uEyTI7FYFnZEzWKY25O FQNCaR8oL+2MkTBN6ocGJQgiDQ2qGT+T7a/t19vmajUk0ov8VAdhaC/yByLNS7bQJOX4 3GhbseMEG9qPF1FFoFVbskVFZ/Rh1hO95rBbWBhaDzs3pcQi3xjyHAr+W6Dz9y6LaHJi 5C38nBVCBl2ovLw9EUkxlPBLgJ8gvenNVQU71lLqI4B8Aph0wydo1+pFuCJk5ZFCHFnV Jnqw== X-Gm-Message-State: AOAM5306fITPalTwuPVpwZF/wzEUHmN8bUBWAzQH9NogYHucnXfZFV/O bKEbMb79QGT6/8ZMtxO9g0URyyxrl2TnMui971iapLVR X-Google-Smtp-Source: ABdhPJyCUol4h225ibfdgf3Jy311kXgBRVjVSzQWrRCBbfv77xoPEuKheCtOWWFlnucf5iy3PKPK7K7qcKWfP896FJk= X-Received: by 2002:a62:8303:: with SMTP id h3mr1814729pfe.169.1596993109816; Sun, 09 Aug 2020 10:11:49 -0700 (PDT) MIME-Version: 1.0 References: <20200808175251.582781-1-xie.he.0141@gmail.com> In-Reply-To: From: Xie He Date: Sun, 9 Aug 2020 10:11:39 -0700 Message-ID: Subject: Re: [PATCH net] drivers/net/wan/lapbether: Added needed_tailroom To: Willem de Bruijn Cc: "David S. Miller" , Jakub Kicinski , Network Development , linux-kernel , Linux X25 , Martin Schiller Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Aug 9, 2020 at 1:48 AM Willem de Bruijn wrote: > > Does this solve an actual observed bug? > > In many ways lapbeth is similar to tunnel devices. This is not common. Thank you for your comment! This doesn't solve a bug observed by me. But I think this should be necessary considering the logic of the code. Using "grep", I found that there were indeed Ethernet drivers that set needed_tailroom. I found it was set in these files: drivers/net/ethernet/sun/sunvnet.c drivers/net/ethernet/sun/ldmvsw.c Setting needed_tailroom may be necessary for this driver to run those Ethernet devices.