From patchwork Thu Jul 2 03:34:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanley Chu X-Patchwork-Id: 11637819 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EE93E6C1 for ; Thu, 2 Jul 2020 03:35:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D64452083E for ; Thu, 2 Jul 2020 03:35:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="iN7IUOpd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726896AbgGBDfE (ORCPT ); Wed, 1 Jul 2020 23:35:04 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:20722 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725857AbgGBDfE (ORCPT ); Wed, 1 Jul 2020 23:35:04 -0400 X-UUID: 32f0e419367a415bb4c3a376fc4a9b5d-20200702 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=O8tR3m1usHUyKyTLuqtgxgifBOAcJvs4RhW300Axtyc=; b=iN7IUOpdM60nFIddzEpaCCTf0nsW6aiHatJa5NusX4xna0sJey4i8wj+Ne9tc3GToHwsd/blN77dU2okKRmPY8QC54FrudvUU0yhKapvfhL6V7Ysx3PLNpPXs38eZC7ywhxc+O1SbWqTBmpSCA0ihkkDcYwYNr+FtvO373DCCB4=; X-UUID: 32f0e419367a415bb4c3a376fc4a9b5d-20200702 Received: from mtkcas08.mediatek.inc [(172.21.101.126)] by mailgw01.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.10 Build 0809 with TLS) with ESMTP id 1812564571; Thu, 02 Jul 2020 11:35:00 +0800 Received: from MTKCAS06.mediatek.inc (172.21.101.30) by mtkmbs08n1.mediatek.inc (172.21.101.55) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 2 Jul 2020 11:34:51 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by MTKCAS06.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 2 Jul 2020 11:34:52 +0800 From: Stanley Chu To: , , , , , CC: , , , , , , , , , , , , , Stanley Chu Subject: [RFC PATCH v2] scsi: ufs: Quiesce all scsi devices before shutdown Date: Thu, 2 Jul 2020 11:34:51 +0800 Message-ID: <20200702033451.26635-1-stanley.chu@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-MTK: N Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Currently I/O request could be still submitted to UFS device while UFS is working on shutdown flow. This may lead to racing as below scenarios and finally system may crash due to unclocked register accesses. To fix this kind of issues, specifically quiesce all SCSI devices before UFS shutdown to block all I/O request sending from block layer. Example of racing scenario: While UFS device is runtime-suspended Thread #1: Executing UFS shutdown flow, e.g., ufshcd_suspend(UFS_SHUTDOWN_PM) Thread #2: Executing runtime resume flow triggered by I/O request, e.g., ufshcd_resume(UFS_RUNTIME_PM) This breaks the assumption that UFS PM flows can not be running concurrently and some unexpected racing behavior may happen. Signed-off-by: Stanley Chu --- drivers/scsi/ufs/ufshcd.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 59358bb75014..18da2d64f9fa 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -8599,10 +8599,27 @@ EXPORT_SYMBOL(ufshcd_runtime_idle); int ufshcd_shutdown(struct ufs_hba *hba) { int ret = 0; + struct scsi_target *starget; if (!hba->is_powered) goto out; + /* + * Quiesce all SCSI devices to prevent any non-PM requests sending + * from block layer during and after shutdown. + * + * Here we can not use blk_cleanup_queue() since PM requests + * (with BLK_MQ_REQ_PREEMPT flag) are still required to be sent + * through block layer. Therefore SCSI command queued after the + * scsi_target_quiesce() call returned will block until + * blk_cleanup_queue() is called. + * + * Besides, scsi_target_"un"quiesce (e.g., scsi_target_resume) can + * be ignored since shutdown is one-way flow. + */ + list_for_each_entry(starget, &hba->host->__targets, siblings) + scsi_target_quiesce(starget); + if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba)) goto out;