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, URIBL_BLOCKED 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 0C0A7C433DB for ; Sat, 6 Mar 2021 00:58:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB87565077 for ; Sat, 6 Mar 2021 00:58:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229969AbhCFA6U (ORCPT ); Fri, 5 Mar 2021 19:58:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229982AbhCFA6B (ORCPT ); Fri, 5 Mar 2021 19:58:01 -0500 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6383CC06175F; Fri, 5 Mar 2021 16:58:01 -0800 (PST) Received: by mail-pj1-x102d.google.com with SMTP id t9so149972pjl.5; Fri, 05 Mar 2021 16:58:01 -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=kEB+wkg0VXlo2zJ9VMKwJrG0JtlezJmZdygKl69AD+I=; b=Doc9qVn0UogV3W56hb+iDnp3/OyBQwHdTQoy7LTDlplAxNfNnocU+qQ3IkdqnUXP5v lkfNGz+Am9fJ8/hjJ8TLLgHZQDNusq+UjFzAPt/Eaq2Ut1y98WIu20C5AT3vXyTwRTlL JMhSikGXh0djRA3q0N512fL30yaLx75QFbSMw967PrhFx/q08ZYJV+t+RWO5k/spW/RA xqhJSvQ0lYBIfr7ibgnFoF+tXkQyCBIkupU+SA32QUnYMrmyfaJQoOe9ia8e3Optp+xE +mjpqdYeLvTT6uv3E2Jl7J8svGQdkAfeKzqTrpr2Oyg7Id11PVFtJgGxl0vUTOIB6bZa qesA== 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=kEB+wkg0VXlo2zJ9VMKwJrG0JtlezJmZdygKl69AD+I=; b=ZBfAoRgqdVg95tMY0MpwiINlYYd7qMqCUFjW9nAlM71Q3/y0H3Alfl2AIcU0LXM+cl ORqSQDk00i0HZuNpk+pwvN4ioXWXAcBnOp7MtQOV3Pb6zZ3xBSptWox/oIp3C9Wu6akO bQGrSZB4XP+dWwT80DRZtepoI7cY6yJYJpWcf76ky8t+/5QyQxfmRNkcMeaO0FySRJTG fWyCxTAA40wr1sET55Eag65M7gLQpYM3g8n6vZgcNMekEtesRzOvrNHpq8AiXsBU4cE5 /VQzseW8dz0310pkdQM9zogpCQUNYeAwsc77RRRbxenwE+eVeWbXXdCZrQgXEd8+xSZI bmbQ== X-Gm-Message-State: AOAM532Z9xxlbQn5cu+wmfx3KMpYfNM28DyrDwk1VjvamC42ROSV2NlN lPI3qsQ/J9pyAzY7CNrhN51L17fFRmoyH1q90ZCF2rEpe1u0pw== X-Google-Smtp-Source: ABdhPJwbxFnpZfNws7VuiKzvxh4mG1T4EJ4x0sGRb61EkDmpZw5e4yJed6mgSIVWcC278lMexvUfahJHOrdUTC+QYFY= X-Received: by 2002:a17:90a:8594:: with SMTP id m20mr12810495pjn.215.1614992280821; Fri, 05 Mar 2021 16:58:00 -0800 (PST) MIME-Version: 1.0 References: <20210302023743.24123-1-xiyou.wangcong@gmail.com> <20210302023743.24123-3-xiyou.wangcong@gmail.com> <6042cc5f4f65a_135da20824@john-XPS-13-9370.notmuch> In-Reply-To: <6042cc5f4f65a_135da20824@john-XPS-13-9370.notmuch> From: Cong Wang Date: Fri, 5 Mar 2021 16:57:49 -0800 Message-ID: Subject: Re: [Patch bpf-next v2 2/9] sock: introduce sk_prot->update_proto() To: John Fastabend Cc: Lorenz Bauer , Networking , bpf , duanxiongchun@bytedance.com, Dongdong Wang , Jiang Wang , Cong Wang , Daniel Borkmann , Jakub Sitnicki Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Mar 5, 2021 at 4:27 PM John Fastabend wrote: > > Cong Wang wrote: > > On Tue, Mar 2, 2021 at 10:23 AM Cong Wang wrote: > > > > > > On Tue, Mar 2, 2021 at 8:22 AM Lorenz Bauer wrote: > > > > > > > > On Tue, 2 Mar 2021 at 02:37, Cong Wang wrote: > > > > > > > > ... > > > > > static inline void sk_psock_restore_proto(struct sock *sk, > > > > > struct sk_psock *psock) > > > > > { > > > > > sk->sk_prot->unhash = psock->saved_unhash; > > > > > > > > Not related to your patch set, but why do an extra restore of > > > > sk_prot->unhash here? At this point sk->sk_prot is one of our tcp_bpf > > > > / udp_bpf protos, so overwriting that seems wrong? > > "extra"? restore_proto should only be called when the psock ref count > is zero and we need to transition back to the original socks proto > handlers. To trigger this we can simply delete a sock from the map. > In the case where we are deleting the psock overwriting the tcp_bpf > protos is exactly what we want.? Why do you want to overwrite tcp_bpf_prots->unhash? Overwriting tcp_bpf_prots is correct, but overwriting tcp_bpf_prots->unhash is not. Because once you overwrite it, the next time you use it to replace sk->sk_prot, it would be a different one rather than sock_map_unhash(): // tcp_bpf_prots->unhash == sock_map_unhash sk_psock_restore_proto(); // Now tcp_bpf_prots->unhash is inet_unhash ... sk_psock_update_proto(); // sk->sk_proto is now tcp_bpf_prots again, // so its ->unhash now is inet_unhash // but it should be sock_map_unhash here Thanks.