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 DB341C678D7 for ; Tue, 10 Jan 2023 18:39:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239717AbjAJSjh (ORCPT ); Tue, 10 Jan 2023 13:39:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239618AbjAJSiZ (ORCPT ); Tue, 10 Jan 2023 13:38:25 -0500 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F229843192; Tue, 10 Jan 2023 10:33:51 -0800 (PST) Received: by mail-pf1-x431.google.com with SMTP id c26so5109703pfp.10; Tue, 10 Jan 2023 10:33:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=KsouuxBuiJc8vCJmbxhsGZquFChD89mMF5fleuPLAHA=; b=D1xx5iOXYizVGZVmUvuz9gRyo14PnGlDQ6ranZeCRfesSPH8+Qnz4auvd5EtnC0PE8 MgHP/5WpYr/2G7BerNwWDjje1kCygPwKyDHSkS1+JGa7oAnZ9bcnrPKioWVbtH4I8Ryn db3M9NylNS+zcLnako5DP2hGo/vHzlHySxJQqhz7coImcT/ibiJhXMNUudg7tzekFWsN LmEPtrzPrTqeCbF4HrZ8seNfARqO4pGKuC0b7MVsdctCiRtutKrpXYypFDvmcppzvHUT ou2I6QDlhQqfwxIpNdSaMXod5hCHrKWtixZdSqaqAiji9CtnHmno4Oq5afQtpYf7CLrL JHag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=KsouuxBuiJc8vCJmbxhsGZquFChD89mMF5fleuPLAHA=; b=VMH+148sM1EmukXsp7IMol80NAhg5oaWUjvyeavGk+bKVFMC1wzsSkG0YUvF1RA3MC /Au98wJjedrE/peCe+46WSIFe6Mqff9o2NEda5M5Krx4u7zJycgsSiJD7WNiz6Rsr3hI uF7JuzWUPlUNhzRGE/e6z2WnrIHL81pL/2e97Za2zdnMnUGzTnNDbTIKoaOTn150MHSK w/BHKOiKMZye07LwmopyMX/3x6Gop4HVVeF1vw6F3FcivfnWcDmK9gWyK5pYnkM23XUN 71ZonbivI7j4N4oO+WojphK3VHrzEyXwFjWDtW0vuAbHK8Temgh9Qa6UELv8SO5MAT4G UBDA== X-Gm-Message-State: AFqh2kqTGymroRQrvhG7HT1b+OVlwSz8TzS+bMhF8zjMVUcHlIeh1lhw Xd2E+DI0DBQQMvXF4FKmEtQ= X-Google-Smtp-Source: AMrXdXsWYPTxoousUtpq9sVyFa/er9qVXOf9kYAZG7rErauBT29M3xD6Lax0ObNnEeh1iAkFj72Obg== X-Received: by 2002:a62:2903:0:b0:56b:f51d:820a with SMTP id p3-20020a622903000000b0056bf51d820amr67420322pfp.7.1673375631351; Tue, 10 Jan 2023 10:33:51 -0800 (PST) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id p62-20020a622941000000b0058130f1eca1sm8348609pfp.182.2023.01.10.10.33.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Jan 2023 10:33:51 -0800 (PST) Sender: Tejun Heo Date: Tue, 10 Jan 2023 08:33:49 -1000 From: Tejun Heo To: Christoph Hellwig Cc: axboe@kernel.dk, josef@toxicpanda.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] blkcg: Restructure blkg_conf_prep() and friends Message-ID: References: <20230105212432.289569-1-tj@kernel.org> <20230105212432.289569-3-tj@kernel.org> <20230110070929.GH10289@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230110070929.GH10289@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 10, 2023 at 08:09:29AM +0100, Christoph Hellwig wrote: > On Thu, Jan 05, 2023 at 11:24:30AM -1000, Tejun Heo wrote: > > * blkg_conf_open_bdev() is updated to take a pointer to blkg_conf_ctx like > > blkg_conf_prep() and can be called multiple times safely. Instead of > > modifying the double pointer to input string directly, > > blkg_conf_open_bdev() now sets blkg_conf_ctx->body. > > This looks pretty awkward for the externals callers of blkcg_conf_open_bdev > in blk-iocost. I'd either keep the calling conventions as they are > at the moment, or just open code blkcg_conf_open_bdev in blk-iocost. Because we're coming in from cgroupfs, we aren't synchronizing properly against blkdevs going away. For all config attempt coming in from cgroup side, we'll need to synchronize explicitly and these config helper blocks look like a good place to do so. Please take a look at the thread with Yu Kuai. Imma update the comment to include that but yeah let's keep it this way for that. Thanks. -- tejun