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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 66210C3279B for ; Tue, 10 Jul 2018 06:33:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1408420881 for ; Tue, 10 Jul 2018 06:33:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Vq/9j6Ta" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1408420881 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1751351AbeGJGdn (ORCPT ); Tue, 10 Jul 2018 02:33:43 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:53380 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129AbeGJGdh (ORCPT ); Tue, 10 Jul 2018 02:33:37 -0400 Received: by mail-it0-f66.google.com with SMTP id a195-v6so28885797itd.3; Mon, 09 Jul 2018 23:33:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RXvCm2b1RxOO65ySOZT2fw2NttHpGPva4cEEbYYtFSI=; b=Vq/9j6TaJJIcN728vFTw2hmRVE9EYTxjYto5KTj50L0EKxBvL4mts73rP07ZbUuSz+ hGNJ+3ViFaK/uqlvmr7gV9ny/lJvP6S/LBV4yGc0uaHJXOreYLfNxdNdQqOTpPVNHnCp TsV/1GhZikou5EB/E89cmamcw55F8Wyo9JRIdaHdgi4najZByo57lby7IIxHIK1L6r1t TnuZKz89YBP0vsdlmyD4xCUApJH9SRh1pRGNtx0V+/NdKuiExnVHNaoi2/XBThP4siAv 8jJ1O1wzEp/pks6FdJN7flUq0UW7SqFOvCx6DPCH7UFHcRzP1lefszfKPjKIGX6LvqSn U2Nw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RXvCm2b1RxOO65ySOZT2fw2NttHpGPva4cEEbYYtFSI=; b=rLN/0vNbLAZs4/2hfkABFk0oiifQJ7qcjy51z4QmRjRpeYWNqFGqFpFBjYAtK8k0LW BjyRVHW5jJyJr2/z3TwH2FqEsdRxIq1XtiCJExuYNKmnEbFPmAFMAgxlzC9RFLgriRWc pqk8zV4zRk/TLZ08OZ2eEWDjbJ0LXo7yRrdd0CZpa8xJQRPhpvHbscsEnNjebr8CFwGo Qt/ZOiM/z9yo10RlaS8CMIh4EVZ/rZytDG9SNv40UBJBZDr5SRTzeUVbLa3C/1LFMnVz PeJbCFrPfM44tLfW1K5y1WG8MBJqYAvmFXkmrDpfv1ru05P4Nk9KYYCM5TNMmkR0fF4T YDBg== X-Gm-Message-State: APt69E2VNlo9jTn0HUF+4d9JVHaAdEEn53TRE1bHY5FCA472goG5YPMY 2iUYbmyQ2FQxB3/IJOIWTAPcD2/GxYLPRA0IIw== X-Google-Smtp-Source: AAOMgpew48GwZS2CP1N8koZweFZcYgBJ0vjxMDHKye6dpLjmCnoZtRGIVDVR6T+kiZyCsSZ2X/Z8D3DKYzm1DeK0wnU= X-Received: by 2002:a02:8c94:: with SMTP id f20-v6mr19276348jak.98.1531204417257; Mon, 09 Jul 2018 23:33:37 -0700 (PDT) MIME-Version: 1.0 References: <1530600642-25090-1-git-send-email-kernelfans@gmail.com> <2108146.dv4EAOf6IP@aspire.rjw.lan> <8816662.k3KXbdkA2e@aspire.rjw.lan> In-Reply-To: <8816662.k3KXbdkA2e@aspire.rjw.lan> From: Pingfan Liu Date: Tue, 10 Jul 2018 14:33:25 +0800 Message-ID: Subject: Re: [PATCH] driver core: Drop devices_kset_move_last() call from really_probe() To: rjw@rjwysocki.net Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Grygorii Strashko , Christoph Hellwig , Bjorn Helgaas , Dave Young , linux-pci@vger.kernel.org, lukas@wunner.de, linux-pm@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 6, 2018 at 6:01 PM Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > The devices_kset_move_last() call in really_probe() is a mistake > as it may cause parents to follow children in the devices_kset list > which then causes system shutdown to fail. Namely, if a device has > children before really_probe() is called for it (which is not > uncommon), that call will cause it to be reordered after the children > in the devices_kset list and the ordering of that list will not > reflect the correct device shutdown order. > > Also it causes the devices_kset list to be constantly reordered > until all drivers have been probed which is totally pointless > overhead in the majority of cases. > > For that reason, revert the really_probe() modifications made by > commit 52cdbdd49853. > > Fixes: 52cdbdd49853 (driver core: correct device's shutdown order) > Link: https://lore.kernel.org/lkml/CAFgQCTt7VfqM=UyCnvNFxrSw8Z6cUtAi3HUwR4_xPAc03SgHjQ@mail.gmail.com/ > Reported-by: Pingfan Liu > Signed-off-by: Rafael J. Wysocki > --- > drivers/base/dd.c | 8 -------- > 1 file changed, 8 deletions(-) > > Index: linux-pm/drivers/base/dd.c > =================================================================== > --- linux-pm.orig/drivers/base/dd.c > +++ linux-pm/drivers/base/dd.c > @@ -434,14 +434,6 @@ re_probe: > goto probe_failed; > } > > - /* > - * Ensure devices are listed in devices_kset in correct order > - * It's important to move Dev to the end of devices_kset before > - * calling .probe, because it could be recursive and parent Dev > - * should always go first > - */ > - devices_kset_move_last(dev); > - > if (dev->bus->probe) { > ret = dev->bus->probe(dev); > if (ret) > Tested-by: Pingfan Liu