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=-24.0 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 5C382C07E9C for ; Thu, 8 Jul 2021 16:46:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41C6661451 for ; Thu, 8 Jul 2021 16:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229644AbhGHQsq (ORCPT ); Thu, 8 Jul 2021 12:48:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbhGHQsq (ORCPT ); Thu, 8 Jul 2021 12:48:46 -0400 Received: from mail-yb1-xb2e.google.com (mail-yb1-xb2e.google.com [IPv6:2607:f8b0:4864:20::b2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53764C06175F for ; Thu, 8 Jul 2021 09:46:04 -0700 (PDT) Received: by mail-yb1-xb2e.google.com with SMTP id k184so9939562ybf.12 for ; Thu, 08 Jul 2021 09:46:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=C8aJuBtMFzTRHA7lVP8ggKa6+OtDRqlwkTJ4zp7YVbA=; b=m2cxjbPU1NSMTUyOORYLxJ0yJPmYYSMS6OxzDvZTtFbsnMH+Ot23bNJpv/3h/PvsAQ wuwOcPYtcx6bb3PqzxripTgjY7O8QhK6TnU4eirzRoxxY9lkHe9/yd7KWl8PkzQz4bg1 WyDnUViuKF6FwO293DmW0zD8F2DYITDltL2xKkvQ7lNXVnP3u8sYNKCEp2/32TqTsKdb K6yPK3jse7H4m6YIYrN/UQk8SN8WuncPaGo+YjCoRqzPcDReF1P19QMIngBA0daWQgBp LhXNeajwwiA8v21pGlYcMVWqSVLUjINqCp5UndIBta85cMU7iLxVbyfw6CQIfAX8owma hISg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=C8aJuBtMFzTRHA7lVP8ggKa6+OtDRqlwkTJ4zp7YVbA=; b=mZF9xhTozK37F2LpIyjW6KMqxtc+t3H/zKDmB4ef+gQnLSkz4daUlVD/bReEjIXsYN FYF1FCi+Iwel9Hqo37unpCMSeM1L+WGntjEtHtSSjJT7Hl8oBZwCVopmP1YXAI7jZ9Kt lAZp33HYSljqzUfFURiq7KPL0EYmyQfkD7L94t8t5/vJ1qZV6Z2AkJuS0BAw+itvMqk+ BEAU64JjyJTW9Ek7qFN02zDNaed6jJASU4lvZpVgPGlUPZY4XLPcW7wx+pXX8E/bf/lw gu5XPUzxUXb2MH5F+1sxsu97MFD/4rbuczqyrZKX5CFzZaTDwHN5p/y3ifOtIZbc/0YN Uf8w== X-Gm-Message-State: AOAM5308+bYA7EVbfAvowVlddXu2xj6Fu/xXpCutMXq02dkpPUgo9i3m bmjKq6rjBALucbHNN1ZILpZZs/9WoKA3OQyXML7cvw== X-Google-Smtp-Source: ABdhPJwB3mFvuPjBuouBnVJ2WKh37PWsmDCUs7owmMr3YwI4DjL6FalRU/lXkkhreClSaM5YzUR6kZbEGVtXz4mx4b8= X-Received: by 2002:a25:b3c8:: with SMTP id x8mr41042585ybf.466.1625762763268; Thu, 08 Jul 2021 09:46:03 -0700 (PDT) MIME-Version: 1.0 References: <20210707172948.1025-1-adrian.hunter@intel.com> <20210707172948.1025-3-adrian.hunter@intel.com> <66130101-b0c5-a9a3-318a-468c6f3b380f@intel.com> In-Reply-To: From: Saravana Kannan Date: Thu, 8 Jul 2021 09:45:27 -0700 Message-ID: Subject: Re: [PATCH RFC 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe To: Adrian Hunter Cc: "Rafael J. Wysocki" , Greg Kroah-Hartman , "Martin K . Petersen" , "James E . J . Bottomley" , "open list:TARGET SUBSYSTEM" , Avri Altman , Bean Huo , Can Guo , Asutosh Das , Bart Van Assche , Linux PM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 8, 2021 at 7:17 AM Adrian Hunter wrote: > > On 8/07/21 3:31 pm, Rafael J. Wysocki wrote: > > On Wed, Jul 7, 2021 at 7:49 PM Adrian Hunter wrote: > >> > >> On 7/07/21 8:39 pm, Greg Kroah-Hartman wrote: > >>> On Wed, Jul 07, 2021 at 08:29:48PM +0300, Adrian Hunter wrote: > >>>> If a LUN fails to probe (e.g. absent BOOT WLUN), the device will not have > >>>> been registered but can still have a device link holding a reference to the > >>>> device. The unwanted device link will prevent runtime suspend indefinitely, > >>>> and cause some warnings if the supplier is ever deleted (e.g. by unbinding > >>>> the UFS host controller). Fix by explicitly deleting the device link when > >>>> SCSI destroys the SCSI device. > >>>> > >>>> Signed-off-by: Adrian Hunter > >>>> --- > >>>> drivers/scsi/ufs/ufshcd.c | 7 +++++++ > >>>> 1 file changed, 7 insertions(+) > >>>> > >>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > >>>> index 708b3b62fc4d..483aa74fe2c8 100644 > >>>> --- a/drivers/scsi/ufs/ufshcd.c > >>>> +++ b/drivers/scsi/ufs/ufshcd.c > >>>> @@ -5029,6 +5029,13 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev) > >>>> spin_lock_irqsave(hba->host->host_lock, flags); > >>>> hba->sdev_ufs_device = NULL; > >>>> spin_unlock_irqrestore(hba->host->host_lock, flags); > >>>> + } else { > >>>> + /* > >>>> + * If a LUN fails to probe (e.g. absent BOOT WLUN), the device > >>>> + * will not have been registered but can still have a device > >>>> + * link holding a reference to the device. > >>>> + */ > >>>> + device_links_scrap(&sdev->sdev_gendev); > >>> > >>> What created that link? And why did it do that before probe happened > >>> successfully? > >> > >> The same driver created the link. > >> > >> The documentation seems to say it is allowed to, if it is the consumer. > >> From Documentation/driver-api/device_link.rst > >> > >> Usage > >> ===== > >> > >> The earliest point in time when device links can be added is after > >> :c:func:`device_add()` has been called for the supplier and > >> :c:func:`device_initialize()` has been called for the consumer. > > > > Yes, this is allowed, but if you've added device links to a device > > object that is not going to be registered after all, you are > > responsible for doing the cleanup. > > > > Why can't you call device_link_del() directly on those links? > > > > Or device_link_remove() if you don't want to deal with link pointers? > > > > Those only work for DL_FLAG_STATELESS device links, but we use only > DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE flags. Is there a reason you can't use DL_FLAG_STATELESS? It doesn't preclude you from using RPM_ACTIVE as far as I can tell. -Saravana -Saravana