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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EBB53C3F2CE for ; Wed, 4 Mar 2020 17:05:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C381021D56 for ; Wed, 4 Mar 2020 17:05:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583341546; bh=1+DglH2uThysUvnGM8zZCA2dvGMU+M93V9n272VCqSQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=L/myN64eSIz/8zOjKuI+3udVG6vKIuqvXY24DPE8Da6kyWRUwOuV1vvXzpiHOqZcz rUl/vjZo9ympd2H3yACJIAnvFWylS77zlA6CN7ccMGp0sdWnpp2xu+IIoXc8zBO3k8 mkfkRfO3ah3B+GF/2VtkEezhFKMTzDvbZAwtTIM8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729386AbgCDRFq (ORCPT ); Wed, 4 Mar 2020 12:05:46 -0500 Received: from mail-qt1-f195.google.com ([209.85.160.195]:39262 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726561AbgCDRFp (ORCPT ); Wed, 4 Mar 2020 12:05:45 -0500 Received: by mail-qt1-f195.google.com with SMTP id e13so1903841qts.6; Wed, 04 Mar 2020 09:05:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=rm/wY9qTRCYlSnYi7ajYS41w3MJHXh7lvSvmNYrIYmY=; b=lf2V1wlJt8iXzR7OvwB4+2OOnWEpUGUjD33V+3a3QzABSqB2wUIYpXrNVNACOJ4Qdn 1BhXqlhH7TJLGETDcDQ/jgsz97xoVEs80+CkKXxndvYQnIfoMWvDjnYCJsO8FaKAgQy+ oR9V/M8IpiCK1U9MMsaGvhn/zsjweFjovgRBnVpDc6arygzLlm2PMkUVvKYNQSw6NieJ RBvLIqWXt+aD1rcpe6CuZjGG6SixxA3rH0FFtRxZrC+DR10cHn3T0KV4otNJ2qI8m6QD bw7y1rdA3mZAks9//JR4NxMZh5LdKXtu5jPWM7cEdBf6i83XDYextg4LrcJtTpYGrM5Z vlCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=rm/wY9qTRCYlSnYi7ajYS41w3MJHXh7lvSvmNYrIYmY=; b=aqp4lTFMRTv005sY3TOrjTmAAvD2fkeE+25GfpYBVPUIh/QgsZupEXx4r6gOCtqdDc MLtJtH6a/jMVEfrdGus9kby6ILJrWu3nX7zJ7fQ2UamE92ll3lmC4d6hnwXr7UHC/awE SVKRUDp7jxnP4CweCICkDh6tOR/pdzrbck7Vu3sRdgKdLjZ8Z1YQdo8On/ffcH4SaAXS CVfaHrnBMXDrTx5oCHUFo0k/aVdZE6mx+Hw4c66cYYplVNnV+2ZhGR7cCWS7VUAdPZ73 zKM9yoZEbupOTFvbWQYPVSf6Q2nInEitVKsiu/3UcXXQXcWGFB7n0fPb7A/8AEZNTe/C Dv8Q== X-Gm-Message-State: ANhLgQ2Hyv0lk3JZidOAXwpd00JrG8jFhkShMm2u5zsKks/WZ6+7zgx0 ETS7wiw8HkHvSnu6NURpsZp0zTORqjc= X-Google-Smtp-Source: ADFU+vvOynOG/87P2m7w78DeEu27ls/UoQfjeinD++wR/z+tOJMImGK0FlkzzMclryg4RqKHCh85xw== X-Received: by 2002:ac8:8c6:: with SMTP id y6mr3322931qth.388.1583341545015; Wed, 04 Mar 2020 09:05:45 -0800 (PST) Received: from localhost ([2620:10d:c091:480::1:16fa]) by smtp.gmail.com with ESMTPSA id 65sm14206261qtc.4.2020.03.04.09.05.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Mar 2020 09:05:44 -0800 (PST) Date: Wed, 4 Mar 2020 12:05:43 -0500 From: Tejun Heo To: Yufen Yu Cc: axboe@kernel.dk, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, jack@suse.cz, bvanassche@acm.org, tytso@mit.edu, Greg Kroah-Hartman Subject: Re: [PATCH v2 3/7] bdi: protect device lifetime with RCU Message-ID: <20200304170543.GJ189690@mtj.thefacebook.com> References: <20200226111851.55348-1-yuyufen@huawei.com> <20200226111851.55348-4-yuyufen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200226111851.55348-4-yuyufen@huawei.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hello, It might be better to put this patch at the end rather than in the middle so that when this patch is applied things are actually fixed. > +struct bdi_rcu_device { > + struct device dev; > + struct rcu_head rcu_head; > +}; (cc'ing Greg) Greg, block layer switches association between backing_device_info and its struct device and needs to protect it with RCU. Yufen did so by introducing a wrapping struct around struct device like above. Do you think it'd make sense to just embed rcu_head into struct device and let put_device() to RCU release by default? Thanks. -- tejun