From patchwork Fri Jul 16 11:44:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adrian Hunter X-Patchwork-Id: 479496 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 7FA9DC12002 for ; Fri, 16 Jul 2021 11:44:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6103B60238 for ; Fri, 16 Jul 2021 11:44:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235582AbhGPLrG (ORCPT ); Fri, 16 Jul 2021 07:47:06 -0400 Received: from mga04.intel.com ([192.55.52.120]:40164 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234803AbhGPLrE (ORCPT ); Fri, 16 Jul 2021 07:47:04 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10046"; a="208902317" X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="208902317" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2021 04:44:09 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,244,1620716400"; d="scan'208";a="467107154" Received: from ahunter-desktop.fi.intel.com ([10.237.72.79]) by fmsmga008.fm.intel.com with ESMTP; 16 Jul 2021 04:44:06 -0700 From: Adrian Hunter To: "Rafael J . Wysocki" Cc: Greg Kroah-Hartman , Saravana Kannan , "Martin K . Petersen" , "James E . J . Bottomley" , linux-scsi@vger.kernel.org, Avri Altman , Bean Huo , Can Guo , Asutosh Das , Bart Van Assche , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V4 2/2] scsi: ufshcd: Fix device links when BOOT WLUN fails to probe Date: Fri, 16 Jul 2021 14:44:08 +0300 Message-Id: <20210716114408.17320-3-adrian.hunter@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210716114408.17320-1-adrian.hunter@intel.com> References: <20210716114408.17320-1-adrian.hunter@intel.com> Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Precedence: bulk List-ID: X-Mailing-List: linux-scsi@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 --- 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 2de8f7d8cf54..983e895d4ced 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -887,6 +887,8 @@ 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 708b3b62fc4d..9864a8ee0263 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -5020,15 +5020,34 @@ 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); /* 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); + } } }