{"id":2220595,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2220595/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260407153532.6395-3-djeffery@redhat.com/","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/1.1/projects/28/?format=json","name":"Linux PCI development","link_name":"linux-pci","list_id":"linux-pci.vger.kernel.org","list_email":"linux-pci@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260407153532.6395-3-djeffery@redhat.com>","date":"2026-04-07T15:35:29","name":"[2/5] driver core: do not always lock parent in shutdown","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"f762748dc815dc4117298e7510d7ba530221e588","submitter":{"id":24471,"url":"http://patchwork.ozlabs.org/api/1.1/people/24471/?format=json","name":"David Jeffery","email":"djeffery@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260407153532.6395-3-djeffery@redhat.com/mbox/","series":[{"id":498998,"url":"http://patchwork.ozlabs.org/api/1.1/series/498998/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/list/?series=498998","date":"2026-04-07T15:35:27","name":"shut down devices asynchronously","version":13,"mbox":"http://patchwork.ozlabs.org/series/498998/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2220595/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2220595/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=RI14z00S;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=linux-pci+bounces-52082-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com\n header.b=\"RI14z00S\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=170.10.133.124","smtp.subspace.kernel.org;\n dmarc=pass (p=quarantine dis=none) header.from=redhat.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=redhat.com"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fqr6f4G8Cz1xtJ\n\tfor ; Wed, 08 Apr 2026 01:42:18 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby tor.lore.kernel.org (Postfix) with ESMTP id 0F03930F7A7B\n\tfor ; Tue, 7 Apr 2026 15:36:42 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 8B33D3C5552;\n\tTue, 7 Apr 2026 15:36:19 +0000 (UTC)","from us-smtp-delivery-124.mimecast.com\n (us-smtp-delivery-124.mimecast.com [170.10.133.124])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id C6A9C3C1973\n\tfor ; Tue, 7 Apr 2026 15:36:08 +0000 (UTC)","from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-516-EltgH6WzOTqdn50Q92ivvQ-1; Tue,\n 07 Apr 2026 11:36:00 -0400","from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n\t(No client certificate requested)\n\tby mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 1275418005BA;\n\tTue, 7 Apr 2026 15:35:57 +0000 (UTC)","from fedora-work.redhat.com (unknown [10.22.80.127])\n\tby mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id DCD97180035F;\n\tTue, 7 Apr 2026 15:35:51 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775576175; cv=none;\n b=cuFBkAT8TVPDjy7Mj+53FVBw7TwIrNqNZaYoSWmBv0xyVPX9T7sD+MmxSYa+imMkwD4jy0tKpDl1sBtdk4XCq8aGDkKXCK8cLX6xOmcjbu+Ung3cgcSGFwtE7Sgo8ALeidLgkwH61g70jrE+xG5Wfj6t37gFqbOAYyH5SB6y6M0=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775576175; c=relaxed/simple;\n\tbh=LwF4g3GgiBopq5VLyCEXnqlJVDeMdGzjLGWlnJ5pbBY=;\n\th=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:\n\t MIME-Version;\n b=stzDRvGKn7W6L56rhTJVo8R6Jk0u926g3RPRbTOEZ5HdXdwA0yn5CnfP9LdQmoJk2pZrqaEmhFZZ8sE9AFH7DrboPLCf96OyUKxvp4nmEFj5jIeY3Ua/dxI3qhkJBhmXAcrpEF15JEi8eJxXwwHTtD/Q6LzSu2jPPx6X2DUfjzQ=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dmarc=pass (p=quarantine dis=none) header.from=redhat.com;\n spf=pass smtp.mailfrom=redhat.com;\n dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com\n header.b=RI14z00S; arc=none smtp.client-ip=170.10.133.124","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n\ts=mimecast20190719; t=1775576164;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding:\n\t in-reply-to:in-reply-to:references:references;\n\tbh=Xf8VBa3s5TDbzdGc7YU+V5MBvNbOIU1Be5qZpIougPY=;\n\tb=RI14z00SUCmTWktqV8nC6iozWs4/m0AGXfWINzYopAH/1hgaYWUwBTo44xGVUgvaPRGOFh\n\tY7EsFJX3iT5WH5VUzd/9BG+ZxpT3tjR21rHpunaDyGSruyxfHuw0Y1yFzlCV1OG22NvjSG\n\tnF+p+FA6o8sRpCTviyfjBXE76/8Sl9w=","X-MC-Unique":"EltgH6WzOTqdn50Q92ivvQ-1","X-Mimecast-MFC-AGG-ID":"EltgH6WzOTqdn50Q92ivvQ_1775576158","From":"David Jeffery ","To":"linux-kernel@vger.kernel.org,\n\tdriver-core@lists.linux.dev,\n\tlinux-pci@vger.kernel.org,\n\tlinux-scsi@vger.kernel.org,\n\tGreg Kroah-Hartman ,\n\t\"Rafael J. Wysocki\" ,\n\tDanilo Krummrich ","Cc":"Tarun Sahu , Pasha Tatashin ,\n\t=?utf-8?b?TWljaGHFgiBDxYJhcGnFhHNraQ==?= ,\n Jordan Richards , Ewan Milne ,\n John Meneghini , \"Lombardi,\n Maurizio\" , Stuart Hayes ,\n Laurence Oberman , Bart Van Assche ,\n Bjorn Helgaas ,\n \"Martin K . Petersen\" ,\n David Jeffery ","Subject":"[PATCH 2/5] driver core: do not always lock parent in shutdown","Date":"Tue, 7 Apr 2026 11:35:29 -0400","Message-ID":"<20260407153532.6395-3-djeffery@redhat.com>","In-Reply-To":"<20260407153532.6395-1-djeffery@redhat.com>","References":"<20260407153532.6395-1-djeffery@redhat.com>","Precedence":"bulk","X-Mailing-List":"linux-pci@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.111"},"content":"Don't lock a parent device unless it is needed in device_shutdown. This\nis in preparation for making device shutdown asynchronous, when it will\nbe needed to allow children of a common parent to shut down\nsimultaneously.\n\nAnd only acquire a reference to the parent device if the parent is to be\nlocked.\n\nSigned-off-by: Stuart Hayes \nSigned-off-by: David Jeffery \nTested-by: Laurence Oberman \n---\n drivers/base/core.c | 30 ++++++++++++++++--------------\n 1 file changed, 16 insertions(+), 14 deletions(-)","diff":"diff --git a/drivers/base/core.c b/drivers/base/core.c\nindex fabd17be1175..0fb2f3ccc3bd 100644\n--- a/drivers/base/core.c\n+++ b/drivers/base/core.c\n@@ -4784,13 +4784,8 @@ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)\n \treturn error;\n }\n \n-static void shutdown_one_device(struct device *dev)\n+static void __shutdown_one_device(struct device *dev)\n {\n-\tstruct device *parent = dev->parent;\n-\n-\t/* hold lock to avoid race with probe/release */\n-\tif (parent)\n-\t\tdevice_lock(parent);\n \tdevice_lock(dev);\n \n \t/* Don't allow any more runtime suspends */\n@@ -4813,10 +4808,23 @@ static void shutdown_one_device(struct device *dev)\n \t}\n \n \tdevice_unlock(dev);\n-\tif (parent)\n+}\n+\n+static void shutdown_one_device(struct device *dev)\n+{\n+\tstruct device *parent;\n+\n+\t/* hold lock if needed to avoid race with probe/release */\n+\tif (dev->bus && dev->bus->need_parent_lock &&\n+\t (parent = get_device(dev->parent))) {\n+\t\tdevice_lock(parent);\n+\t\t__shutdown_one_device(dev);\n \t\tdevice_unlock(parent);\n+\t\tput_device(parent);\n+\t} else {\n+\t\t__shutdown_one_device(dev);\n+\t}\n \n-\tput_device(parent);\n \tput_device(dev);\n }\n \n@@ -4842,12 +4850,6 @@ void device_shutdown(void)\n \t\tdev = list_entry(devices_kset->list.prev, struct device,\n \t\t\t\tkobj.entry);\n \n-\t\t/*\n-\t\t * hold reference count of device's parent to\n-\t\t * prevent it from being freed because parent's\n-\t\t * lock is to be held\n-\t\t */\n-\t\tget_device(dev->parent);\n \t\tget_device(dev);\n \t\t/*\n \t\t * Make sure the device is off the kset list, in the\n","prefixes":["2/5"]}