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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7D48CCFA13 for ; Wed, 29 Apr 2026 17:52:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:content-type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fb0axA2F4uBUU3oNRkOoe05jXOarYOs75I9L8oq7gEE=; b=Yhi66w8ovFFPI+I+heNnj3bNrz X1asCPSt0J+TEhLtqdY8UO4PouZK9w6Fn+cjTAKv784UfRD/4IhUb30HLYZNDVTut0H021WDOcykb uoxqkNOpyi87bMRTSuMrvJr+J6wlAjF76jEsm2OowFjjb9whi8A94Q/Os+D8bFp85xghbbYelFp4i nKCjb4YnenyRB9oNZUlWu4BaZr/4YAvJ3a3HZW8FolM4m/Ar2tAM65qdWAWBFkoRFoPWVuYV1DARz u7TtzSAL77XmktfegzliBU3jJXSGmkTrWxDCyqR4VQ2UmGlObrPmHIOXcqvrYTX4CaIa3QHSFIFLw jsL+ahVg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wI95S-00000003zvv-1eTi; Wed, 29 Apr 2026 17:52:38 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wI95O-00000003zuc-1rOa for kexec@lists.infradead.org; Wed, 29 Apr 2026 17:52:35 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777485153; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fb0axA2F4uBUU3oNRkOoe05jXOarYOs75I9L8oq7gEE=; b=ZHpGzzgFcUmLhVl3686CqAkPNPx9F01ALzrWG1QPrrqFG4y8aHaIk6ZuV9GvXSmEyD5ECB ti2Lriy0re55cxcqTlaTsQ3LUH4IGUAGUqXkx9/wLZS5l+4MbxkeHXzRmWsWW53iS4iE6w Opvb0UMaIf9yD5mpPY8LX+IApnkA3l0= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-12-NLJua771MEuaxlitmQs91Q-1; Wed, 29 Apr 2026 13:51:02 -0400 X-MC-Unique: NLJua771MEuaxlitmQs91Q-1 X-Mimecast-MFC-AGG-ID: NLJua771MEuaxlitmQs91Q_1777485060 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4EF2D18004A9; Wed, 29 Apr 2026 17:50:59 +0000 (UTC) Received: from fedora-work.redhat.com (unknown [10.22.80.165]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 998C030001A1; Wed, 29 Apr 2026 17:50:53 +0000 (UTC) From: David Jeffery To: linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich Cc: Tarun Sahu , Pasha Tatashin , =?UTF-8?q?Micha=C5=82=20C=C5=82api=C5=84ski?= , Jordan Richards , Ewan Milne , John Meneghini , "Lombardi, Maurizio" , Stuart Hayes , Laurence Oberman , Bart Van Assche , Bjorn Helgaas , "Martin K . Petersen" , John Garry , kexec@lists.infradead.org, David Jeffery , Pasha Tatashin Subject: [PATCH 2/5] driver core: do not always lock parent in shutdown Date: Wed, 29 Apr 2026 13:50:13 -0400 Message-ID: <20260429175016.7915-3-djeffery@redhat.com> In-Reply-To: <20260429175016.7915-1-djeffery@redhat.com> References: <20260429175016.7915-1-djeffery@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-MFC-PROC-ID: Faa_WbU5N-s5WtzdR4EEifuTOX5fY6uesJH4b5qXP4k_1777485060 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260429_105234_555136_61D380A8 X-CRM114-Status: GOOD ( 18.21 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org Don't lock a parent device unless it is needed in device_shutdown. This is in preparation for making device shutdown asynchronous, when it will be needed to allow children of a common parent to shut down simultaneously. And only acquire a reference to the parent device if the parent is to be locked. Signed-off-by: Stuart Hayes Signed-off-by: David Jeffery Tested-by: Laurence Oberman Reviewed-by: Martin K. Petersen Reviewed-by: Pasha Tatashin --- drivers/base/core.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 90ef21c1e713..00979555995f 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4799,13 +4799,8 @@ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) return error; } -static void shutdown_one_device(struct device *dev) +static void __shutdown_one_device(struct device *dev) { - struct device *parent = dev->parent; - - /* hold lock to avoid race with probe/release */ - if (parent) - device_lock(parent); device_lock(dev); /* Don't allow any more runtime suspends */ @@ -4828,10 +4823,23 @@ static void shutdown_one_device(struct device *dev) } device_unlock(dev); - if (parent) +} + +static void shutdown_one_device(struct device *dev) +{ + struct device *parent; + + /* hold lock if needed to avoid race with probe/release */ + if (dev->bus && dev->bus->need_parent_lock && + (parent = get_device(dev->parent))) { + device_lock(parent); + __shutdown_one_device(dev); device_unlock(parent); + put_device(parent); + } else { + __shutdown_one_device(dev); + } - put_device(parent); put_device(dev); } @@ -4857,12 +4865,6 @@ void device_shutdown(void) dev = list_entry(devices_kset->list.prev, struct device, kobj.entry); - /* - * hold reference count of device's parent to - * prevent it from being freed because parent's - * lock is to be held - */ - get_device(dev->parent); get_device(dev); /* * Make sure the device is off the kset list, in the -- 2.53.0