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=-9.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 88C2DC4338F for ; Mon, 23 Aug 2021 10:33:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E2B26137B for ; Mon, 23 Aug 2021 10:33:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236108AbhHWKeB (ORCPT ); Mon, 23 Aug 2021 06:34:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:50362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233118AbhHWKeA (ORCPT ); Mon, 23 Aug 2021 06:34:00 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4BC3A6137F; Mon, 23 Aug 2021 10:33:18 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mI7GW-006dXU-A9; Mon, 23 Aug 2021 11:33:16 +0100 Date: Mon, 23 Aug 2021 11:33:15 +0100 Message-ID: <878s0sqwlw.wl-maz@kernel.org> From: Marc Zyngier To: Barry Song <21cnbao@gmail.com> Cc: Bjorn Helgaas , Bjorn Helgaas , Jonathan Corbet , Jonathan.Cameron@huawei.com, bilbao@vt.edu, Greg Kroah-Hartman , leon@kernel.org, LKML , linux-pci@vger.kernel.org, Linuxarm , luzmaximilian@gmail.com, mchehab+huawei@kernel.org, schnelle@linux.ibm.com, Barry Song , Thomas Gleixner Subject: Re: [PATCH v2 1/2] PCI/MSI: Fix the confusing IRQ sysfs ABI for MSI-X In-Reply-To: References: <20210820223744.8439-2-21cnbao@gmail.com> <20210820233328.GA3368938@bjorn-Precision-5520> <877dgfqdsg.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: 21cnbao@gmail.com, helgaas@kernel.org, bhelgaas@google.com, corbet@lwn.net, Jonathan.Cameron@huawei.com, bilbao@vt.edu, gregkh@linuxfoundation.org, leon@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxarm@huawei.com, luzmaximilian@gmail.com, mchehab+huawei@kernel.org, schnelle@linux.ibm.com, song.bao.hua@hisilicon.com, tglx@linutronix.de X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 21 Aug 2021 23:41:17 +0100, Barry Song <21cnbao@gmail.com> wrote: [...] > > So probably we should set this ABI invisible when devices are using > > MSI or MSI-X? > > i mean something like the below, > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 5d63df7..1323841 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -26,6 +26,7 @@ > #include > #include > #include > +#include > #include > #include "pci.h" > > @@ -1437,6 +1438,16 @@ static umode_t pci_dev_attrs_are_visible(struct > kobject *kobj, > if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA) > return 0; > > +#ifdef CONFIG_PCI_MSI > + /* > + * if devices are MSI and MSI-X, IRQ sysfs ABI is meaningless > + * and broken > + */ > + if (a == &dev_attr_irq.attr) > + if (first_pci_msi_entry(pdev)) > + return 0; > +#endif > + > return a->mode; > } I don't think you can break what we have today. Whatever change we make to the kernel internals, the userspace view must stay unchanged. M. -- Without deviation from the norm, progress is not possible.