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=-0.8 required=3.0 tests=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 C73A3C432C3 for ; Sun, 1 Dec 2019 20:56:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A5F5A215E5 for ; Sun, 1 Dec 2019 20:56:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727296AbfLAU40 (ORCPT ); Sun, 1 Dec 2019 15:56:26 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:53788 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725887AbfLAU4Z (ORCPT ); Sun, 1 Dec 2019 15:56:25 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:1c3::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 59A8114F64DD2; Sun, 1 Dec 2019 12:56:24 -0800 (PST) Date: Sun, 01 Dec 2019 12:56:21 -0800 (PST) Message-Id: <20191201.125621.1568040486743628333.davem@davemloft.net> To: dsahern@gmail.com Cc: prashantbhole.linux@gmail.com, mst@redhat.com, jasowang@redhat.com, ast@kernel.org, daniel@iogearbox.net, jakub.kicinski@netronome.com, hawk@kernel.org, john.fastabend@gmail.com, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, netdev@vger.kernel.org, qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: Re: [RFC net-next 08/18] tun: run offloaded XDP program in Tx path From: David Miller In-Reply-To: References: <20191126100744.5083-1-prashantbhole.linux@gmail.com> <20191126100744.5083-9-prashantbhole.linux@gmail.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]); Sun, 01 Dec 2019 12:56:25 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: David Ahern Date: Sun, 1 Dec 2019 09:39:54 -0700 > Below you just drop the packet which is going to be a bad user > experience. A better user experience is to detect XDP return codes a > program uses, catch those that are not supported for this use case and > fail the install of the program. This is not universally possible. Return codes can be calculated dynamically, come from maps potentially shared with other bpf programs, etc. So unfortunately this suggestion is not tenable.