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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 877F5C07E9C for ; Thu, 8 Jul 2021 12:31:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C8FE613C8 for ; Thu, 8 Jul 2021 12:31:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231433AbhGHMeJ (ORCPT ); Thu, 8 Jul 2021 08:34:09 -0400 Received: from mail-ot1-f44.google.com ([209.85.210.44]:43968 "EHLO mail-ot1-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229659AbhGHMeH (ORCPT ); Thu, 8 Jul 2021 08:34:07 -0400 Received: by mail-ot1-f44.google.com with SMTP id i12-20020a05683033ecb02903346fa0f74dso5632589otu.10; Thu, 08 Jul 2021 05:31:25 -0700 (PDT) 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=8NbbxqFq1+bnPl6bXmT9IRtDnEnfSxRPSocv3xOtk8g=; b=imrznStF9Q20u6HrXZal+4a1Do0dxHQOFgZW8qcnz0PvkyPWAXUcWoIZzqpQUiyA5b jDt1qC/BLGd/tA8+e8zf+2oCx1q5wuLvxDwqTHYZsRzUFgCXlnywlumTHsGf/rhfNtYa lnyo/ShEmU+VSOE/TDRP5MxgsWmXDOlbiCDBQsIZJ5qQfNC109IY6T0eJuf6LvViH/N/ 2jugfgUW0rIFYy8kqigrEDqt++3c19yJbbH3S+RR/UemJJb+P2x/UKn/i7MIwtoRrGj2 0dQx6ZVm1CgG/LAUu7QyHSq63zO3JxwvfCWUhVYihQExI2R87bAeetcUSZwStKt64o+V vmiw== X-Gm-Message-State: AOAM531FUyX1k2tkNjkYyoSrHdlmxrgxJiPScYoxRDE7Pr3uAS3ZmUbk AR69W67JriTo1JRmz19SbVsF75okzs/mdq44qA8= X-Google-Smtp-Source: ABdhPJyj3pCWjeWLPgnpvDjaFKZ/Rjv0erHMWtpAneJA8jAWQrRGqbYu0Sk/GL8IqTWy0lp3Mu/oOKuo5z6v7jI/WxU= X-Received: by 2002:a9d:604e:: with SMTP id v14mr23489241otj.260.1625747484877; Thu, 08 Jul 2021 05:31:24 -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: <66130101-b0c5-a9a3-318a-468c6f3b380f@intel.com> From: "Rafael J. Wysocki" Date: Thu, 8 Jul 2021 14:31:13 +0200 Message-ID: Subject: Re: [PATCH RFC 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe To: Adrian Hunter Cc: Greg Kroah-Hartman , "Rafael J . Wysocki" , Saravana Kannan , "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 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?