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=-5.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 A47CBC0044D for ; Mon, 16 Mar 2020 10:35:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FB2920663 for ; Mon, 16 Mar 2020 10:35:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="heFrLMeY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730690AbgCPKfd (ORCPT ); Mon, 16 Mar 2020 06:35:33 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:40563 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730582AbgCPKfd (ORCPT ); Mon, 16 Mar 2020 06:35:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584354932; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rxa5ZQUiWPk0xLoE7r0pviacnRX8yq/R/jdIfcniPtQ=; b=heFrLMeYY/ea1AGeKz4kSR3SGfTm3rMi4kYahE1j6YYnydpfKr6bNTsK4mx27auo+5KvIX yTF0sQeqOiZukqoghMj4XHqC2nuXdt+YaeS+//5gb8uovYCeOe1TQqs8Jfsqg5B3WdOcK1 ERm8TNj5DtL2quY2nX/bjY8hOA8ms+k= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-155-2iu4k6TKPfCBluwbLdf-gA-1; Mon, 16 Mar 2020 06:35:26 -0400 X-MC-Unique: 2iu4k6TKPfCBluwbLdf-gA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C39F3107ACC4; Mon, 16 Mar 2020 10:35:24 +0000 (UTC) Received: from carbon (ovpn-200-32.brq.redhat.com [10.40.200.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 825F35D9E2; Mon, 16 Mar 2020 10:35:18 +0000 (UTC) Date: Mon, 16 Mar 2020 11:35:15 +0100 From: Jesper Dangaard Brouer To: Edward Cree Cc: David Miller , , , , , , , , brouer@redhat.com Subject: Re: [PATCH net-next] sfc: fix XDP-redirect in this driver Message-ID: <20200316113515.16f7e243@carbon> In-Reply-To: <98fd3c0c-225b-d64c-a64f-ca497205d4ce@solarflare.com> References: <158410589474.499645.16292046086222118891.stgit@firesoul> <20200316.014927.1864775444299469362.davem@davemloft.net> <98fd3c0c-225b-d64c-a64f-ca497205d4ce@solarflare.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 16 Mar 2020 10:10:01 +0000 Edward Cree wrote: > On 16/03/2020 08:49, David Miller wrote: > > Solarflare folks, please review. =20 > > This looks like a correct implementation of what it purports to do, so > Acked-by: Edward Cree Thanks for the review! > It did take me some digging to understand _why_ it was needed though; > =C2=A0Jesper, is there any documentation of the tailroom requirement?=C2= =A0 It > =C2=A0doesn't seem to be mentioned anywhere I could find. I admit that is is poorly documented. It is a requirement as both cpumap and veth have a dependency when they process the redirected packet. We/I also need to update the doc on one page per packet requirement, as it is (in-practice) no longer true. I'm noticing these bugs, because I'm working on a patchset that add tailroom extend, and also reserves this 'skb_shared_info' tailroom area. The real goal is to later add XDP multi-buffer support, using this 'skb_shared_info' tailroom area, as desc here[2] [2] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-m= ulti-buffer01-design.org > (Is there even any up-to-date doc of the XDP driver interface?=C2=A0 The > =C2=A0one at [1] looks a bit stale...) > -Ed >=20 > [1]: https://prototype-kernel.readthedocs.io/en/latest/networking/XDP/des= ign/requirements.html This is my old and out-dated documentation. I didn't know people were still referring to this. I does score quite high on Google, so I guess, that I really need to update this documentation. (It was my plan that this would be merged into kernel tree, but I can see it have been bit-rotting for too long). --=20 Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer