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=-2.7 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 C3146C433E6 for ; Mon, 1 Feb 2021 16:15:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 937CB64E2B for ; Mon, 1 Feb 2021 16:15:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231321AbhBAQPb (ORCPT ); Mon, 1 Feb 2021 11:15:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230055AbhBAQPX (ORCPT ); Mon, 1 Feb 2021 11:15:23 -0500 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78F00C06174A; Mon, 1 Feb 2021 08:14:42 -0800 (PST) Received: by mail-pj1-x1031.google.com with SMTP id a20so10599838pjs.1; Mon, 01 Feb 2021 08:14:42 -0800 (PST) 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=oe9kyxs1vAX/uhUOjLvSRTrrpJNRpCHgV3q3Ra/fPlI=; b=ftDEwVWojYxl00NqeNgdsQPlGCHIBg9DH+l7sy8IYd265AqJ48Wq9qdDTLcfWtBfHg SydNN2Fki+4FWKcIs+47Y4TNFN6kChxWYRh1KH7vQJ8S72cvL/q74WCYqxunfrkbnYQe +fzSBITqpRCl3zxUezpAwtBbNAzcrHOupprKpvbZLY3aZdm3bC63uPiDxwNqeJmsSah0 pv1W2dPBpYKFfkATUNJAayGLkCaLQN0kNBQn8fBKJMKRDWheXudgCSGEQ3W/q9sxVlN/ WZHAkqXZ0TYhhlC264IG/5kuRNfLwSyPfEmHQi+q79r5Y9xVTybwdlMagM/EDRfYWGEY yF4g== 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=oe9kyxs1vAX/uhUOjLvSRTrrpJNRpCHgV3q3Ra/fPlI=; b=qt5/zmSuEyGQhwljGp6tmDI7GH5X+QU5VWDzoubju52TX7TfbI1e7mmo7AaGQ++oIl Miha30TxdCzrKzeU6WnQGF6UjLkX0j9WgdHJcEqLbEBbHSCN5BIexMShdPrJ6HhT7dKy aW3co8dn5wNwuStZlBTFbnRAxHzaQCuj98k7nX+DvU8td254TXmjCfN3o7DxODK6MJiA 925iSErnqvctboaAc0NHzIEtNSAKfnsZuOrU7kM3eZH+ModKDR+tgdrZg2W7T5BtwsQy uQ2Z7zyS0YqVIaOH7cWRMn8//cOV2HXjWmA1FKw8+5iNU6/NqAvxYBeo16u8aUTcgXjB zntQ== X-Gm-Message-State: AOAM533Ox+GwiAZ+xNLzMRhqwn2BizpUYC8t2Z1cvhiiKhl4x/V4U/yb Fp1oSSKvpcd1N3u4rY6jXaKIKSHQFvGkBnNuRckMnWlrhmo= X-Google-Smtp-Source: ABdhPJxT6Mxmrz5OerQe235Y2SgSMqeIpwXqfTzNlzHlwdrw98+9dxUJHindUHj4W1Q58OPz8L7ysGA5UuEAZD1Ggj0= X-Received: by 2002:a17:90a:5403:: with SMTP id z3mr18184163pjh.198.1612196082127; Mon, 01 Feb 2021 08:14:42 -0800 (PST) MIME-Version: 1.0 References: <20210201055706.415842-1-xie.he.0141@gmail.com> <4d1988d9-6439-ae37-697c-d2b970450498@linux.ibm.com> In-Reply-To: <4d1988d9-6439-ae37-697c-d2b970450498@linux.ibm.com> From: Xie He Date: Mon, 1 Feb 2021 08:14:31 -0800 Message-ID: Subject: Re: [PATCH net] net: lapb: Copy the skb before sending a packet To: Julian Wiedmann Cc: "David S. Miller" , Jakub Kicinski , Linux X25 , Linux Kernel Network Developers , LKML , Martin Schiller Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 1, 2021 at 6:10 AM Julian Wiedmann wrote: > > This sounds a bit like you want skb_cow_head() ... ? Calling "skb_cow_head" before we call "skb_clone" would indeed solve the problem of writes to our clones affecting clones in other parts of the system. But since we are still writing to the skb after "skb_clone", it'd still be better to replace "skb_clone" with "skb_copy" to avoid interference between our own clones.