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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 32A60C433DF for ; Tue, 16 Jun 2020 15:50:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14B0E21473 for ; Tue, 16 Jun 2020 15:50:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322602; bh=PyvlkaWrcbPam4O4e/8ZNE9XZyO8pT0w6I3T8D0LlBQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZPedQNAjBLOiLGOfgqKrkaEl5xZ97mVqpXhF2eptz1ZwTEPrBbvI5j3GQzKrOCb3L aA0HZrg1kzwhdLs8v3PG7NbQ0RtqU/5+AjMNBQt1VJMhu156p2eYEumKOe1fh5mJI2 B9LV7W2GvN4LBhgFtEEBCMdEypUE6krrsaGbTi70= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731571AbgFPPt7 (ORCPT ); Tue, 16 Jun 2020 11:49:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:45168 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729999AbgFPPty (ORCPT ); Tue, 16 Jun 2020 11:49:54 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3FD562071A; Tue, 16 Jun 2020 15:49:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322593; bh=PyvlkaWrcbPam4O4e/8ZNE9XZyO8pT0w6I3T8D0LlBQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hq5eQDAeWuws2J9x26nFZskqd03gklzFH2KYdbV+QoQo6ocTMvS7QaySX7k2eXnPO SAg9k9Sttc+RkXomgBOoNA/rXvNj1Y1nP5C+mb4glajDLg8NBx7JfSdaezFFWVg1HL EYJgXAPQz+cPQmrLfIC56n+4xBkGInWe1OAef7tM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Walle , Saravana Kannan , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 5.6 028/161] driver core: Update device link status correctly for SYNC_STATE_ONLY links Date: Tue, 16 Jun 2020 17:33:38 +0200 Message-Id: <20200616153107.740672845@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200616153106.402291280@linuxfoundation.org> References: <20200616153106.402291280@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Saravana Kannan [ Upstream commit 8c3e315d4296421cd26b3300ee0ac117f0877f20 ] When SYNC_STATE_ONLY support was added in commit 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag"), SYNC_STATE_ONLY links were treated similar to STATELESS links in terms of not blocking consumer probe if the supplier hasn't probed yet. That caused a SYNC_STATE_ONLY device link's status to not get updated. Since SYNC_STATE_ONLY device link is no longer useful once the consumer probes, commit 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation") addresses the status update issue by deleting the SYNC_STATE_ONLY device link instead of complicating the status update code. However, there are still some cases where we need to update the status of a SYNC_STATE_ONLY device link. This is because a SYNC_STATE_ONLY device link can later get converted into a normal MANAGED device link when a normal MANAGED device link is created between a supplier and consumer that already have a SYNC_STATE_ONLY device link between them. If a SYNC_STATE_ONLY device link's status isn't maintained correctly till it's converted to a normal MANAGED device link, then the normal MANAGED device link will end up with a wrong link status. This can cause a warning stack trace[1] when the consumer device probes successfully. This commit fixes the SYNC_STATE_ONLY device link status update issue where it wouldn't transition correctly from DL_STATE_DORMANT or DL_STATE_AVAILABLE to DL_STATE_CONSUMER_PROBE. It also resets the status back to DL_STATE_DORMANT or DL_STATE_AVAILABLE if the consumer probe fails. [1] - https://lore.kernel.org/lkml/20200522204120.3b3c9ed6@apollo/ Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag") Fixes: 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation") Reported-by: Michael Walle Tested-by: Michael Walle Signed-off-by: Saravana Kannan Reviewed-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20200526220928.49939-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/base/core.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 68277687c160..3c4ecb824247 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -643,9 +643,17 @@ static void device_links_missing_supplier(struct device *dev) { struct device_link *link; - list_for_each_entry(link, &dev->links.suppliers, c_node) - if (link->status == DL_STATE_CONSUMER_PROBE) + list_for_each_entry(link, &dev->links.suppliers, c_node) { + if (link->status != DL_STATE_CONSUMER_PROBE) + continue; + + if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + } else { + WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } + } } /** @@ -684,11 +692,11 @@ int device_links_check_suppliers(struct device *dev) device_links_write_lock(); list_for_each_entry(link, &dev->links.suppliers, c_node) { - if (!(link->flags & DL_FLAG_MANAGED) || - link->flags & DL_FLAG_SYNC_STATE_ONLY) + if (!(link->flags & DL_FLAG_MANAGED)) continue; - if (link->status != DL_STATE_AVAILABLE) { + if (link->status != DL_STATE_AVAILABLE && + !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) { device_links_missing_supplier(dev); ret = -EPROBE_DEFER; break; @@ -949,11 +957,21 @@ static void __device_links_no_driver(struct device *dev) if (!(link->flags & DL_FLAG_MANAGED)) continue; - if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) + if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { device_link_drop_managed(link); - else if (link->status == DL_STATE_CONSUMER_PROBE || - link->status == DL_STATE_ACTIVE) + continue; + } + + if (link->status != DL_STATE_CONSUMER_PROBE && + link->status != DL_STATE_ACTIVE) + continue; + + if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + } else { + WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } } dev->links.status = DL_DEV_NO_DRIVER; -- 2.25.1