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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 5AC26C433E0 for ; Tue, 26 May 2020 22:09:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35DFF208DB for ; Tue, 26 May 2020 22:09:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="v4zrrqUC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391788AbgEZWJe (ORCPT ); Tue, 26 May 2020 18:09:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389342AbgEZWJe (ORCPT ); Tue, 26 May 2020 18:09:34 -0400 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D15F1C061A0F for ; Tue, 26 May 2020 15:09:33 -0700 (PDT) Received: by mail-qt1-x849.google.com with SMTP id e8so2637138qtq.22 for ; Tue, 26 May 2020 15:09:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:subject:from:to:cc; bh=76RnCrYuIkxjPD/67W4gWQzeBexPbh4E4FGax1pg7M8=; b=v4zrrqUCHGjAdSRZM8NUPTODZaC9BulTFTPNq4ikigV9FNcXtVQAVGLhc8M36bhvwM X/ShDKCg/PBndpbavZqQCgT/GSTPKKjFedavuiBfn4wg7HZp1o8sPwSCohXErk/nyE62 DEI61v5Gepabha43pMC72mKQmQ6vlUKD7JQmpno/x8Y5YxXPlzAEU1PqNlQ6z9jN1ea3 izE8HTWlJANcpx8BrsLedFpwNLvMpfGyXhukAsS8HL/oinP+pIm6tfF5KwFatdpkvg8Z pjp3G5NO+/9RtopQxKyEEXeND71MEhLCgg2PT4iKupbLZIKaKn29JJ93YyS1bGrP0/V+ Q9cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version:subject :from:to:cc; bh=76RnCrYuIkxjPD/67W4gWQzeBexPbh4E4FGax1pg7M8=; b=ThywOYtKFGXf/x8Rcg8JH7UVHsEUC1gSfCjP4SXtnoNWIPBcIpZp24SdalymzH88FR ZLzFP8cMKlCf0i2eiEHuvDDDAsEstnhmKoo6m2BOdi4ijW6dBCaj5GERSvF1ct+emi0B dQy2tV4nyMDgKhW9iT82ySPbSWB2O+5JOLnFb5Avm+tdQksWJS329pJNxhylxm/yaows z3AlyXNE0gZFGu4oqtEEEaXTcaKfEZKKaaHr2Tl+tYgAm6rCNzw030HUQtFBimgnQPcO JSPTk5egJLFn0VUd2SxH4gzBy4ynd0NKS2Jqb9Mn5BPB7jgKn/S2t7Kfm8cx2+ZYCHXS +y9Q== X-Gm-Message-State: AOAM533rn8ejZKgJ1HFTNNoBxJgaO+CZoZL++dVbSpWfIa05JM6LDsTE p0lhrckj5FLvFupCF8WI1tFkkCnxjsDLxCU= X-Google-Smtp-Source: ABdhPJwd/fhrf0rDUhLOAH8yaPymFMnZy4V2MHeWC/+UdErTwcsr+XenVM4ID8s4+rLSowndXcEYmrAnon+uWW0= X-Received: by 2002:a0c:8b99:: with SMTP id r25mr20979191qva.174.1590530972841; Tue, 26 May 2020 15:09:32 -0700 (PDT) Date: Tue, 26 May 2020 15:09:27 -0700 In-Reply-To: <6144404cb26d1f797fd7e87b124bcaf8@walle.cc> Message-Id: <20200526220928.49939-1-saravanak@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.27.0.rc0.183.gde8f92d652-goog Subject: [PATCH v3] driver core: Update device link status correctly for SYNC_STATE_ONLY links From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Saravana Kannan Cc: Michael Walle , kernel-team@android.com, "Rafael J. Wysocki" , linux-kernel@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 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 --- v1->v2: - Added code to "revert" the link status if consumer probe fails v2->v3: - Fixed copy-pasta where I was checking link->status instead of link->flags. 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 791b7530599f..9a76dd44cb37 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -646,9 +646,17 @@ 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); + } + } } /** @@ -687,11 +695,11 @@ 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; @@ -952,11 +960,21 @@ 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; -- 2.27.0.rc0.183.gde8f92d652-goog