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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 F36C6C433E0 for ; Wed, 20 Jan 2021 17:36:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC75C2070A for ; Wed, 20 Jan 2021 17:36:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732413AbhATReu (ORCPT ); Wed, 20 Jan 2021 12:34:50 -0500 Received: from mga17.intel.com ([192.55.52.151]:44636 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727717AbhATR2A (ORCPT ); Wed, 20 Jan 2021 12:28:00 -0500 IronPort-SDR: c4Y1yAfWaSfzy6xi4dnXtv0RmxZpKivZrT6DtHF/YkKQsG3A9mz35RLx2I+u8uCSmYTd/MCpbF w8CN4qtvlzYA== X-IronPort-AV: E=McAfee;i="6000,8403,9870"; a="158920042" X-IronPort-AV: E=Sophos;i="5.79,361,1602572400"; d="scan'208";a="158920042" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jan 2021 09:26:36 -0800 IronPort-SDR: c0DiXwi0jxEJ3f1JM/E3RBGOAU42389H6sGWM//ZuedOqs5nN4SOZPtWNNV0vh36DD8uZWSM00 hE+B6Ibb5d5A== X-IronPort-AV: E=Sophos;i="5.79,361,1602572400"; d="scan'208";a="384942904" Received: from myegin-mobl1.ger.corp.intel.com (HELO btopel-mobl.ger.intel.com) ([10.249.42.133]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jan 2021 09:26:29 -0800 Subject: Re: [PATCH bpf-next v2 1/8] xdp: restructure redirect actions To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: magnus.karlsson@intel.com, maciej.fijalkowski@intel.com, kuba@kernel.org, jonathan.lemon@gmail.com, maximmi@nvidia.com, davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com, ciara.loftus@intel.com, weqaar.a.janjua@intel.com References: <20210119155013.154808-1-bjorn.topel@gmail.com> <20210119155013.154808-2-bjorn.topel@gmail.com> <87bldjeq1j.fsf@toke.dk> <996f1ff7-5891-fd4a-ee3e-fefd7e93879d@intel.com> <87mtx34q48.fsf@toke.dk> <0a7d1a0b-de2e-b973-a807-b9377bb89737@intel.com> <87bldj4lm6.fsf@toke.dk> From: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= Message-ID: <559c6eb8-38b3-4719-2368-397f07daf5a5@intel.com> Date: Wed, 20 Jan 2021 18:26:23 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <87bldj4lm6.fsf@toke.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 2021-01-20 17:30, Toke Høiland-Jørgensen wrote: > Björn Töpel writes: > [...] >> >> It can't be free'd but, ri->map can be cleared via >> bpf_clear_redirect_map(). So, between the helper (setting) and the >> tracepoint in xdp_do_redirect() it can be cleared (say if the XDP >> program is swapped out, prior running xdp_do_redirect()). > > But xdp_do_redirect() should be called on driver flush before exiting > the NAPI cycle, so how can the XDP program be swapped out? > To clarify; xdp_do_redirect() is called for each packet in the NAPI poll loop. Yeah, you're right. The xdp_do_redirect() is within the RCU scope, so the program wont be destroyed (but can be swapped though!). Hmm, so IOW the bpf_clear_redirect_map() is not needed anymore... Björn [...]