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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9539CC00140 for ; Wed, 10 Aug 2022 05:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229563AbiHJFy5 (ORCPT ); Wed, 10 Aug 2022 01:54:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231178AbiHJFyk (ORCPT ); Wed, 10 Aug 2022 01:54:40 -0400 Received: from mail-lj1-x22d.google.com (mail-lj1-x22d.google.com [IPv6:2a00:1450:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EC6F85F96 for ; Tue, 9 Aug 2022 22:54:39 -0700 (PDT) Received: by mail-lj1-x22d.google.com with SMTP id z20so15062547ljq.3 for ; Tue, 09 Aug 2022 22:54:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc; bh=WVbHtZC2AvMLO10Cu7qSYN2iTvF7BVUKT1qBXKTO+AY=; b=fs0/W3ItwIJEwfXeFBVjWuxC1NzwoO2sV+EY10CoQ42no0XTM7Cq8DNfuBZuVNIzkv /J7Ikm94atRiSDOeau+ahzEtkIL9u+u3WsHlLCU7svS2hHGKmbHxpFhNpqMcxYCyHfv7 tit2gdUsuz9KkRkFctJP+pp055CGe6kjdajrW+o/A92SaqYowrm8BQT1Jn0k859wQfAO umPhUe40bhkF5hYmtW2fGP1ZL8nvIPHpRlgrYh2c5SThqParjn93NSZLAZGKJFsamebp QyBngUgpI+z5DPYgsqakl1sz5T4SIEoAL7UQo88iyY36Qir9TKzDWJdwdei04XAkbgjn dC4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc; bh=WVbHtZC2AvMLO10Cu7qSYN2iTvF7BVUKT1qBXKTO+AY=; b=gJgbakXb3dnsbgopFFoFhUE+o9F+G47EoOQJUEOnK+wIhfPohNlUHq7sOmca6yWbvp +h1byZAlKkxUFeXBa3vqDslACyZ9EzsniCtKo48St4Xx4fG/gvF/LzDur7C+q2ownBqp W5CEnsfNUCzCAk4pXRRasHW2QsPKJzGzPkurODVimlzyjm0z5Hv+MgsNyihvKYZLn1VM dxcQOKLlFeRy6MkXwkNaPsQBoCxXRV95uwnJOIxgDFix60cMFZ8ZFKoKypvIeIE9Tfiv tbjQvhiTxSt9IUFgpF58C75RBzLBw8ND5jY5YhwngOyLgC6b5aw9fDM1a0Qd39X6tnfu XXLA== X-Gm-Message-State: ACgBeo1bPH75AFy4TW3NER5/9s3/PqFyamxAAAWWAAVWWq9Qrml29t1e MxQPwmwXqyq6jkbLjkgrP12Re5lCKr+Ce5Ar X-Google-Smtp-Source: AA6agR5q6g8lF1qNjciIR7gC2E+jmBpmyN3QYLleh7NBp4iK85ouPa6pDPs0v95nVr6IP+6DLEACFg== X-Received: by 2002:a05:651c:515:b0:25f:dce6:2e95 with SMTP id o21-20020a05651c051500b0025fdce62e95mr4267107ljp.327.1660110877725; Tue, 09 Aug 2022 22:54:37 -0700 (PDT) Received: from [192.168.1.39] ([83.146.140.105]) by smtp.gmail.com with ESMTPSA id m6-20020a056512114600b0048b038c7624sm216040lfg.42.2022.08.09.22.54.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Aug 2022 22:54:37 -0700 (PDT) Message-ID: Date: Wed, 10 Aug 2022 08:54:36 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [REGRESSION] changes to driver_override parsing broke DPDK script Content-Language: en-US To: Bjorn Helgaas , Stephen Hemminger Cc: bhelgaas@google.com, gregkh@linuxfoundation.org, linux-pci@vger.kernel.org, regressions@lists.linux.dev References: <20220809192102.GA1331186@bhelgaas> From: Krzysztof Kozlowski In-Reply-To: <20220809192102.GA1331186@bhelgaas> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 09/08/2022 22:21, Bjorn Helgaas wrote: > [+cc regressions list] > > 23d99baf9d72 appeared in v5.19-rc1. > > On Tue, Aug 09, 2022 at 11:29:43AM -0700, Stephen Hemminger wrote: >> This commit broke the driver override script in DPDK. >> This is an API/ABI breakage, please revert or fix the commit. >> >> Report of problem: >> http://mails.dpdk.org/archives/dev/2022-August/247794.html Thanks for the report. I'll take a look. >> >> >> commit 23d99baf9d729ca30b2fb6798a7b403a37bfb800 >> Author: Krzysztof Kozlowski >> Date: Tue Apr 19 13:34:28 2022 +0200 >> >> PCI: Use driver_set_override() instead of open-coding >> >> Use a helper to set driver_override to the reduce amount of duplicated >> code. Make the driver_override field const char, because it is not >> modified by the core and it matches other subsystems. >> >> Reviewed-by: Andy Shevchenko >> Acked-by: Bjorn Helgaas >> Signed-off-by: Krzysztof Kozlowski >> Link: https://lore.kernel.org/r/20220419113435.246203-6-krzysztof.kozlowski@linaro.org >> Signed-off-by: Greg Kroah-Hartman >> >> >> The script is sending single nul character to remove override >> and that no longer works. The sysfs API clearly states: "and may be cleared with an empty string (echo > driver_override)." Documentation/ABI/testing/sysfs-bus-pci Sending other data and expecting the same result is not conforming to API. Therefore we have usual example of some undocumented behavior which user-space started relying on and instead using API, user-space expect that undocumented behavior to be back. Yay! I wonder what is the point to even describe the ABI if user-space can simply ignore it? Best regards, Krzysztof