From patchwork Fri Aug 6 13:04:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adrian Hunter X-Patchwork-Id: 493068 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=-20.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_SANE_1 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 13300C4338F for ; Fri, 6 Aug 2021 13:04:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7F3D611CB for ; Fri, 6 Aug 2021 13:04:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343898AbhHFNEd (ORCPT ); Fri, 6 Aug 2021 09:04:33 -0400 Received: from mga11.intel.com ([192.55.52.93]:11073 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343883AbhHFNEb (ORCPT ); Fri, 6 Aug 2021 09:04:31 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10067"; a="211261951" X-IronPort-AV: E=Sophos;i="5.84,300,1620716400"; d="scan'208";a="211261951" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Aug 2021 06:04:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,300,1620716400"; d="scan'208";a="504017952" Received: from ahunter-desktop.fi.intel.com (HELO [10.237.72.174]) ([10.237.72.174]) by fmsmga004.fm.intel.com with ESMTP; 06 Aug 2021 06:04:09 -0700 Subject: [PATCH V5] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe From: Adrian Hunter To: "Martin K. Petersen" , Bart Van Assche Cc: Greg Kroah-Hartman , Saravana Kannan , "James E . J . Bottomley" , linux-scsi@vger.kernel.org, Avri Altman , Bean Huo , Can Guo , Asutosh Das , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, "Rafael J . Wysocki" References: <20210716114408.17320-1-adrian.hunter@intel.com> <20210716114408.17320-3-adrian.hunter@intel.com> <35b2bd0f-5766-debd-2b4c-c642a85df367@acm.org> <739a1abf-fca0-458e-5c8c-1d6ed90b56e0@intel.com> Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: Date: Fri, 6 Aug 2021 16:04:41 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <739a1abf-fca0-458e-5c8c-1d6ed90b56e0@intel.com> Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Managed device links are deleted by device_del(). However it is possible to add a device link to a consumer before device_add(), and then discovering an error prevents the device from being used. In that case normally references to the device would be dropped and the device would be deleted. However the device link holds a reference to the device, so the device link and device remain indefinitely (unless the supplier is deleted). For UFSHCD, 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. Amend device link removal to accept removal of a link with an unregistered consumer device (suggested by Rafael), and fix UFSHCD by explicitly deleting the device link when SCSI destroys the SCSI device. Fixes: b294ff3e34490 ("scsi: ufs: core: Enable power management for wlun") Signed-off-by: Adrian Hunter Reviewed-by: Rafael J. Wysocki --- Patch "driver core: Prevent warning when removing a device link from unregistered consumer" is already in Linus' tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e64daad660a0c9ace3acdc57099fffe5ed83f977 Changes in V5: Rebase on 5.15/scsi-staging drivers/base/core.c | 2 ++ drivers/scsi/ufs/ufshcd.c | 23 +++++++++++++++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index cadcade65825..9badd7f7fe62 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -884,6 +884,8 @@ static void device_link_put_kref(struct device_link *link) { if (link->flags & DL_FLAG_STATELESS) kref_put(&link->kref, __device_link_del); + else if (!device_is_registered(link->consumer)) + __device_link_del(&link->kref); else WARN(1, "Unable to drop a managed device link reference\n"); } diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 6c263e94144b..9f72698ff597 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -5028,6 +5028,7 @@ static int ufshcd_slave_configure(struct scsi_device *sdev) static void ufshcd_slave_destroy(struct scsi_device *sdev) { struct ufs_hba *hba; + unsigned long flags; hba = shost_priv(sdev->host); @@ -5035,11 +5036,29 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev) /* Drop the reference as it won't be needed anymore */ if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN) { - unsigned long flags; - spin_lock_irqsave(hba->host->host_lock, flags); hba->sdev_ufs_device = NULL; spin_unlock_irqrestore(hba->host->host_lock, flags); + } else if (hba->sdev_ufs_device) { + struct device *supplier = NULL; + + /* Ensure UFS Device WLUN exists and does not disappear */ + spin_lock_irqsave(hba->host->host_lock, flags); + if (hba->sdev_ufs_device) { + supplier = &hba->sdev_ufs_device->sdev_gendev; + get_device(supplier); + } + spin_unlock_irqrestore(hba->host->host_lock, flags); + + if (supplier) { + /* + * 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_link_remove(&sdev->sdev_gendev, supplier); + put_device(supplier); + } } }