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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 E9255C4338F for ; Fri, 30 Jul 2021 05:06:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC57260F9B for ; Fri, 30 Jul 2021 05:06:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230221AbhG3FGd (ORCPT ); Fri, 30 Jul 2021 01:06:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:48816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229919AbhG3FGd (ORCPT ); Fri, 30 Jul 2021 01:06:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 618CF60F5E; Fri, 30 Jul 2021 05:06:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627621589; bh=p3nYlqSlxyGAM6AvYRuMMHJgMFqrJ0vuQwZwMKkumJ0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jZMR4AC7lrWNd/KukK5kriDGp0x6JSL1eo4eU+7s9fPPP6V37rcDba5mMtxPAwXEa r7AabwSjDRu/sea2jf6RmF7e4JCccn3k5nQf06nzLcRMIzswB2kGdZr8K6NJ/5gs8g qnJ0qZnP79GXC5clM33OYiW5tenEytb9azLnTEPY= Date: Fri, 30 Jul 2021 07:06:26 +0200 From: Greg Kroah-Hartman To: Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= Cc: Bjorn Helgaas , Dan Williams , Daniel Vetter , Kees Cook , Pali =?iso-8859-1?Q?Roh=E1r?= , Oliver O'Halloran , linux-pci@vger.kernel.org Subject: Re: [PATCH v3 0/2] Allow deferred execution of iomem_get_mapping() Message-ID: References: <20210729233235.1508920-1-kw@linux.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210729233235.1508920-1-kw@linux.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jul 29, 2021 at 11:32:33PM +0000, Krzysztof Wilczyński wrote: > Hello, > > At the moment, the dependency on iomem_get_mapping() that is currently > used in the pci_create_resource_files() and pci_create_legacy_files() > stops us from completely retiring the late_initcall() that is used to > invoke pci_sysfs_init() when creating sysfs object for PCI devices. > > This dependency on iomem_get_mapping() stops us from retiring the > late_initcall at the moment as when we convert dynamically added sysfs > objects, that are primarily added in the pci_create_resource_files() and > pci_create_legacy_files(), as these attributes are added before the VFS > completes its initialisation, and since most of the PCI devices are > typically enumerated in subsys_initcall this leads to a failure and an > Oops related to iomem_get_mapping() access. > > See relevant conversations: > https://lore.kernel.org/linux-pci/20210204165831.2703772-1-daniel.vetter@ffwll.ch/ > https://lore.kernel.org/linux-pci/20210313215747.GA2394467@bjorn-Precision-5520/ > > After some deliberation about the problem at hand, Dan Williams > suggested a solution to the problem, as per: > https://lore.kernel.org/linux-pci/CAPcyv4i0y_4cMGEpNVShLUyUk3nyWH203Ry3S87BqnDJE0Rmxg@mail.gmail.com/ > > The idea is to defer execution of the iomem_get_mapping() to only when > the sysfs open callback is run, and thus removing the reliance of > fs_initcalls to complete before any other sub-system that uses the > iomem_get_mapping(). > > Currently, the PCI sub-system will benefit the most from this change > allowing for it to complete the transition from dynamically created to > static sysfs objects. > > This series aims to take Dan Williams' idea through the finish line. > > Related to: > https://lore.kernel.org/linux-pci/20210527205845.GA1421476@bjorn-Precision-5520/ > https://lore.kernel.org/linux-pci/20210507102706.7658-1-danijel.slivka@amd.com/ > https://lore.kernel.org/linux-pci/20200716110423.xtfyb3n6tn5ixedh@pali/ > > Krzysztof > No objection from me on these, Bjorn, mind if I take them through my driver core tree? thanks, greg k-h