From patchwork Tue Jul 10 12:51:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 10516923 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AA58F6032A for ; Tue, 10 Jul 2018 12:53:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9942328D5A for ; Tue, 10 Jul 2018 12:53:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8C7D728D87; Tue, 10 Jul 2018 12:53:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 26DDA28D5A for ; Tue, 10 Jul 2018 12:53:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933326AbeGJMxJ (ORCPT ); Tue, 10 Jul 2018 08:53:09 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:64113 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933132AbeGJMxG (ORCPT ); Tue, 10 Jul 2018 08:53:06 -0400 Received: from 79.184.255.246.ipv4.supernova.orange.pl (79.184.255.246) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83) id 6f96726e6321e058; Tue, 10 Jul 2018 14:53:03 +0200 From: "Rafael J. Wysocki" To: Greg Kroah-Hartman Cc: Pingfan Liu , linux-kernel@vger.kernel.org, Grygorii Strashko , Christoph Hellwig , Bjorn Helgaas , Dave Young , linux-pci@vger.kernel.org, Lukas Wunner , Linux PM , Kishon Vijay Abraham I Subject: [PATCH v2] driver core: Partially revert "driver core: correct device's shutdown order" Date: Tue, 10 Jul 2018 14:51:33 +0200 Message-ID: <5284251.Resgjlja2Q@aspire.rjw.lan> In-Reply-To: <2927655.Y1qg3UnIrE@aspire.rjw.lan> References: <1530600642-25090-1-git-send-email-kernelfans@gmail.com> <8816662.k3KXbdkA2e@aspire.rjw.lan> <2927655.Y1qg3UnIrE@aspire.rjw.lan> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rafael J. Wysocki Commit 52cdbdd49853 (driver core: correct device's shutdown order) introduced a regression by breaking device shutdown on some systems. Namely, the devices_kset_move_last() call in really_probe() added by that commit is a mistake as it may cause parents to follow children in the devices_kset list which then causes shutdown to fail. For example, 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 any more. 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 and it only covered an issue with system shutdown, while system-wide suspend/resume potentially had the same issue on the affected platforms (which was not covered). Moreover, the shutdown issue originally addressed by the change in really_probe() made by commit 52cdbdd49853 is not present in 4.18-rc any more, since dra7 started to use the sdhci-omap driver which doesn't disable any regulators during shutdown, so the really_probe() part of commit 52cdbdd49853 can be safely reverted. [The original issue was related to the omap_hsmmc driver used by dra7 previously.] For the above reasons, revert the really_probe() modifications made by commit 52cdbdd49853. The other code changes made by commit 52cdbdd49853 are useful and they need not be reverted. 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 Tested-by: Pingfan Liu Reviewed-by: Kishon Vijay Abraham I Signed-off-by: Rafael J. Wysocki --- -> v2: Added information from Kishon on the fact that it should be safe to revert the really_probe() modifications added by the problematic commit. Also added the Reviewed-by tag from Kishon. --- 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)