Received: by 2002:a05:6a10:7420:0:0:0:0 with SMTP id hk32csp2756217pxb; Sat, 19 Feb 2022 23:09:27 -0800 (PST) X-Google-Smtp-Source: ABdhPJzB88evnggxAfPCAlq4SM1r30K3P2fR4y8LfzyrhKZtMdELnlNqDvzxItw+wtlwWKz/Zu9P X-Received: by 2002:a17:906:d9db:b0:6ce:8bfb:53c9 with SMTP id qk27-20020a170906d9db00b006ce8bfb53c9mr11751190ejb.10.1645340967671; Sat, 19 Feb 2022 23:09:27 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1645340967; cv=none; d=google.com; s=arc-20160816; b=1JYdHghgfP3121n4pmYEiSQls/vFLWP9k/WRXFfrePW+H18HLl5RTtTK2liEo+s2HD VD425Q/S782ksLveud59Qy73aEvXrKLArJFsPgXheeV5BJIvb6T3ryTnvl1uZwVgjU+n IdxYxE04uQ6bffNgYlF3dlwpt9rf2zmU6WTxrshjlAHslmnJRZCNLyJLObcX1atfMuiS LQvv11EyJ2g44n6aZsmuYlCCHxPnmzqvVlgAqYO1zMEMKZSzosCvnxE67AzFw9vnbAnH U0F4nRUf4wlP0W2VRYwFvK0TjX9VeoNqOFGYVdqf0dhlaxo+kuG+osqFkMwTIni5Ps6d 2qcw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=wTeVSHhkY0lXDzUgqmz69cQmI3OVeINmghi2Fxg2Gao=; b=jc7wCBkreZHcwyn+IDk36SXEvpXk3Q0qK6WkYNOu5WGhYnLW3SM6/VWB4G/d2OlIV/ 14n3FmVGtCss1dQs4QVP6A8+Bwlm3G/QuGzm+73WstR+xLx+j/xmxYAyVLnWkR6DBxQW UwuY5MbEfneW9vRtYNbMozAX2ZnNKlRFoMlDvcka6UkqYsLBomymQ3T6UbOEWzXjssSj Yn3DArP9lq8utJkz6dySffuhPm2ZxA72NLkC8XStOaQv1AmNOpJ+l3ksLMKicmviykbF kHcfh4Qg/jJ7l2chtOvQWfPxmmPqcpUjbI3EAzZBiCefTVSh+csc6ZHxEv8/7igM948l xhTg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id x7si8669916eds.360.2022.02.19.23.09.05; Sat, 19 Feb 2022 23:09:27 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240023AbiBSF6d (ORCPT + 99 others); Sat, 19 Feb 2022 00:58:33 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:50698 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232729AbiBSF6c (ORCPT ); Sat, 19 Feb 2022 00:58:32 -0500 Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [IPv6:2607:5300:60:148a::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C7DB4DF6B; Fri, 18 Feb 2022 21:58:14 -0800 (PST) Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nLIl3-002v0S-54; Sat, 19 Feb 2022 05:58:13 +0000 Date: Sat, 19 Feb 2022 05:58:13 +0000 From: Al Viro To: Rik van Riel Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, linux-fsdevel@vger.kernel.org, paulmck@kernel.org, gscrivan@redhat.com, Eric Biederman , Chris Mason Subject: Re: [PATCH 1/2] vfs: free vfsmount through rcu work from kern_unmount Message-ID: References: <20220218183114.2867528-1-riel@surriel.com> <20220218183114.2867528-2-riel@surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Al Viro X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 19, 2022 at 05:53:37AM +0000, Al Viro wrote: > On Fri, Feb 18, 2022 at 01:31:13PM -0500, Rik van Riel wrote: > > > struct super_block; > > struct vfsmount; > > @@ -73,6 +74,7 @@ struct vfsmount { > > struct super_block *mnt_sb; /* pointer to superblock */ > > int mnt_flags; > > struct user_namespace *mnt_userns; > > + struct rcu_work free_rwork; > > } __randomize_layout; > > Wait, what? First of all, that has no business being in vfsmount - > everything that deeply internal belongs in struct mount, not in > its public part. Moreover, there's already mount->mnt_rcu, so what's > the point duplicating that? Argh... You need rcu_work there... OK, so make that a member of the same union mnt_rcu is. In struct mount, please. And I'm not sure I like the idea of shoving that much into struct mount, TBH...