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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 63774C4321D for ; Fri, 17 Aug 2018 04:58:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28BC82152D for ; Fri, 17 Aug 2018 04:58:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 28BC82152D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726372AbeHQH7z (ORCPT ); Fri, 17 Aug 2018 03:59:55 -0400 Received: from gate.crashing.org ([63.228.1.57]:34205 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725789AbeHQH7z (ORCPT ); Fri, 17 Aug 2018 03:59:55 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w7H4vegw017530; Thu, 16 Aug 2018 23:57:42 -0500 Message-ID: <8b11e45e969c8407bf063c4d515305eab2b0769d.camel@kernel.crashing.org> Subject: Re: [RFC PATCH 2/6] pci: Set pci_dev->is_added before calling device_add From: Benjamin Herrenschmidt To: Bjorn Helgaas , linux-pci@vger.kernel.org Cc: Hari Vyas , Ray Jui , Srinath Mannam , Guenter Roeck , Jens Axboe , Lukas Wunner , Konstantin Khlebnikov , Marta Rybczynska , Pierre-Yves Kerbrat , linux-kernel@vger.kernel.org Date: Fri, 17 Aug 2018 14:57:40 +1000 In-Reply-To: <20180817044902.31420-3-benh@kernel.crashing.org> References: <20180817044902.31420-1-benh@kernel.crashing.org> <20180817044902.31420-3-benh@kernel.crashing.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-1.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org s/device_add/device_attach .. ugh. On Fri, 2018-08-17 at 14:48 +1000, Benjamin Herrenschmidt wrote: > This re-fixes the bug reported by Hari Vyas > after my revert of his commit but in a much simpler way. > > The main issues is that is_added was being set after the driver > got bound and started, and thus setting it could race with other > changes to struct pci_dev. > > This fixes it by setting the flag first, which also has the > advantage of matching the fact that we are clearing it *after* > unbinding in the remove path, thus the flag is now symtetric > and always set while the driver code is running. > > Signed-off-by: Benjamin Herrenschmidt > --- > drivers/pci/bus.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c > index 35b7fc87eac5..48ae63673aa8 100644 > --- a/drivers/pci/bus.c > +++ b/drivers/pci/bus.c > @@ -321,16 +321,16 @@ void pci_bus_add_device(struct pci_dev *dev) > pci_proc_attach_device(dev); > pci_bridge_d3_update(dev); > > + dev->is_added = 1; > dev->match_driver = true; > retval = device_attach(&dev->dev); > if (retval < 0 && retval != -EPROBE_DEFER) { > + dev->is_added = 0; > pci_warn(dev, "device attach failed (%d)\n", retval); > pci_proc_detach_device(dev); > pci_remove_sysfs_dev_files(dev); > return; > } > - > - dev->is_added = 1; > } > EXPORT_SYMBOL_GPL(pci_bus_add_device); >