From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E13BA134B6 for ; Thu, 5 Oct 2023 20:56:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BnLGK1W3" Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 393881B4 for ; Thu, 5 Oct 2023 13:56:50 -0700 (PDT) Received: by mail-wr1-x42d.google.com with SMTP id ffacd0b85a97d-32325534cfaso1331823f8f.3 for ; Thu, 05 Oct 2023 13:56:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1696539408; x=1697144208; darn=vger.kernel.org; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject:from:to:cc :subject:date:message-id:reply-to; bh=7DAHDrfXtdyG1iqpwyN2VAU+p3Dn2E1eqHCWxsU4Zlw=; b=BnLGK1W3JxsjlZzcPC6z+azEMv+qy/OeOeORhoqwRsuX1/ie+NuZZHkgr1dzaT392b hXiwhhDNstvYcvUuWqGq25c0rKioEV/U2hLJlGK+YLhNn9KXBLqgypAjo5ieSFLIC+AD y/5bG8rGbLjMnPYPUit4aU6d2IVFYM3+LmFY0Hplg9ebb2c7J+23JXEp9ZCbZVAGh1HL xqVaNsbAQyt276BQHpwk4BgLGrfZLsZPcWqJUsjylUOlZqNhYu5Q+JEsV+jDT6QT9O6M e6CcG3zuAq7SEW4rNMcOoFyK/fpgBCxymD9RnAn3yncluy7yuJTtpRNl4NDduv8cCfBZ sy3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696539408; x=1697144208; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7DAHDrfXtdyG1iqpwyN2VAU+p3Dn2E1eqHCWxsU4Zlw=; b=Z+/QdbrlHRyfgKR18h42CdzvWFXye7Z4QlJ1bOn+wqdddf1sjqUuOPc4iu046m6s1A txIQ38rrGlNPd/6iMMfkxIZ8PKqJ/5KFhTr3Eke8ff9jRVBfLB1KBgzBBOGvE842+M+o sYNkBQNWjzEqjo+SrQfu7t4EPVmF3wUnfsgCMjUdKJIrT2hvUPycxqBEp+Zq0BTur4cn 7/s3w5+kwWHo73O0ZfmVHGpX9mj/oTUVSFqkECCYTAClBkYEV4x2rvmG0esN2UL5RC3j 3KcTV8OOzj6oIzJ+XVpi9McvhttVkS6VnCCaY4+Afiz5riPIcwwYbhdtDvGQaD8xpYpw ZGkQ== X-Gm-Message-State: AOJu0Yw8KaEohkolcX3lnsw5TeaB0jVcHc1BuGopeKCwzw+zVWrr0/8h MsTQdrB+c+MaVqs/LdcKLX4= X-Google-Smtp-Source: AGHT+IGDYzPNgrXWA8qBk5sEVaUSdTaKytdHg6KwqdrpfPj21vEh0KRc/Vc7D/Ih/6dwAimXMsTneg== X-Received: by 2002:a5d:6548:0:b0:327:e070:15b8 with SMTP id z8-20020a5d6548000000b00327e07015b8mr5912047wrv.41.1696539408560; Thu, 05 Oct 2023 13:56:48 -0700 (PDT) Received: from [192.168.1.122] (cpc159313-cmbg20-2-0-cust161.5-4.cable.virginm.net. [82.0.78.162]) by smtp.gmail.com with ESMTPSA id f15-20020a5d50cf000000b00323330edbc7sm19537wrt.20.2023.10.05.13.56.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Oct 2023 13:56:48 -0700 (PDT) Subject: Re: [PATCH v4 net-next 6/7] net: ethtool: add a mutex protecting RSS contexts To: Jakub Kicinski , edward.cree@amd.com Cc: linux-net-drivers@amd.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org, habetsm.xilinx@gmail.com, sudheer.mogilappagari@intel.com, jdamato@fastly.com, andrew@lunn.ch, mw@semihalf.com, linux@armlinux.org.uk, sgoutham@marvell.com, gakula@marvell.com, sbhatta@marvell.com, hkelam@marvell.com, saeedm@nvidia.com, leon@kernel.org References: <20231004161651.76f686f3@kernel.org> From: Edward Cree Message-ID: <70e5af64-b696-dec1-1afd-730559b96bfd@gmail.com> Date: Thu, 5 Oct 2023 21:56:47 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20231004161651.76f686f3@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 05/10/2023 00:16, Jakub Kicinski wrote: > On Wed, 27 Sep 2023 19:13:37 +0100 edward.cree@amd.com wrote: >> While this is not needed to serialise the ethtool entry points (which >> are all under RTNL), drivers may have cause to asynchronously access >> dev->ethtool->rss_ctx; taking dev->ethtool->rss_lock allows them to >> do this safely without needing to take the RTNL. > > Can we use a replay mechanism, like we do in TC offloads and VxLAN/UDP > ports? The driver which lost config can ask for the rss contexts to be > "replayed" and the core will issue a series of ->create calls for all > existing entries? I like that idea, yes. Will try to implement it for v5. There is a question as to how the core should react if the ->create call then fails; see my reply to Martin on #7. > Regarding the lock itself - can we hide it under ethtool_rss_lock(dev) > / ethtool_rss_unlock(dev) helpers? Sure. If I can't get replay to work then I'll do that. -ed