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=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 769F8C433DB for ; Mon, 8 Feb 2021 09:11:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26A2264E7A for ; Mon, 8 Feb 2021 09:11:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231373AbhBHJLR (ORCPT ); Mon, 8 Feb 2021 04:11:17 -0500 Received: from mailout3.samsung.com ([203.254.224.33]:14754 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231251AbhBHIy7 (ORCPT ); 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Mon, 8 Feb 2021 08:53:48 +0000 (GMT) Received: from epsmges2p2.samsung.com (unknown [182.195.40.188]) by epsnrtp3.localdomain (Postfix) with ESMTP id 4DZ0Dp6hh1z4x9Q7; Mon, 8 Feb 2021 08:53:46 +0000 (GMT) X-AuditID: b6c32a46-1d9ff7000000dbf8-b2-6020fc1a16f1 Received: from epcas2p4.samsung.com ( [182.195.41.56]) by epsmges2p2.samsung.com (Symantec Messaging Gateway) with SMTP id 73.36.56312.A1CF0206; Mon, 8 Feb 2021 17:53:46 +0900 (KST) Mime-Version: 1.0 Subject: RE: Re: [PATCH v19 2/3] scsi: ufs: L2P map management for HPB read Reply-To: daejun7.park@samsung.com Sender: Daejun Park From: Daejun Park To: Can Guo , Daejun Park CC: Greg KH , "avri.altman@wdc.com" , "jejb@linux.ibm.com" , "martin.petersen@oracle.com" , "asutoshd@codeaurora.org" , "stanley.chu@mediatek.com" , "huobean@gmail.com" , "bvanassche@acm.org" , ALIM AKHTAR , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Sung-Jun Park , yongmyung lee , Jinyoung CHOI , BoRam Shin , SEUNGUK SHIN X-Priority: 3 X-Content-Kind-Code: NORMAL In-Reply-To: <88b608e2e133ba7ccd5bb452898848fd@codeaurora.org> X-CPGS-Detection: blocking_info_exchange X-Drm-Type: N,general X-Msg-Generator: Mail X-Msg-Type: PERSONAL X-Reply-Demand: N Message-ID: <20210208085346epcms2p1c11b70be9d258df66cb2ca4542835fac@epcms2p1> Date: Mon, 08 Feb 2021 17:53:46 +0900 X-CMS-MailID: 20210208085346epcms2p1c11b70be9d258df66cb2ca4542835fac Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: AUTO_CONFIDENTIAL X-CPGSPASS: Y X-CPGSPASS: Y CMS-TYPE: 102P X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrMLsWRmVeSWpSXmKPExsWy7bCmha7UH4UEg6XHjS0ezNvGZrG37QS7 xcufV9ksDt9+x24x7cNPZotP65exWrw8pGmx6kG4RfPi9WwWc842MFn09m9ls1h0YxuTxeVd c9gsuq/vYLNYfvwfk8XtLVwWS7feZLTonL6GxWLRwt0sDsIel694e1zu62Xy2DnrLrvHhEUH GD32z13D7tFycj+Lx8ent1g8+rasYvT4vEnOo/1AN1MAV1QDo01iUXJGZlmqQmpecn5KZl66 rVJoiJuuhZJCRn5xia1StKGFkZ6hpameiaWekXmslaGBgZGpkkJeYm6qrVKFLlS3kkJRcgFQ dUlqcUlRanIqUKjIobgkMT1Vrzgxt7g0L10vOT9XSaEsMacUqE9J384mIzUxJbVIIeEJY8a5 nVPZCmYJVfydv52tgXEJbxcjJ4eEgInE/0MNrCC2kMAORol/z3O7GDk4eAUEJf7uEAYJCwt4 S/zqbmKCKFGSWH9xFjtEXE/i1sM1jCA2m4COxPQT98HiIgKeEl8nrwYaycXBLNDAJtF2ajkr xC5eiRntT1kgbGmJ7cu3gjVzCthJTG2/yQQR15D4sayXGcIWlbi5+i07jP3+2HxGCFtEovXe WagaQYkHP3dDxSUlju3+ADWnXmLrnV+MIEdICPQwShzeeQvqCH2Jax0bwY7gFfCVuHX9MpjN IqAq0T/lC1Szi8T5rtlg9cwC8hLb385hBgUKs4CmxPpd+iCmhICyxJFbLDBvNWz8zY7OZhbg k+g4/BcuvmPeE6jpahLrfq5nmsCoPAsR0rOQ7JqFsGsBI/MqRrHUguLc9NRiowIj5HjexAhO +FpuOxinvP2gd4iRiYPxEKMEB7OSCG9gp1yCEG9KYmVValF+fFFpTmrxIcYqoC8nMkuJJucD c05eSbyhmYGRmamxibGxqYkp2cKmRmZmBpamFqZmRhZK4rzFBg/ihQTSE0tSs1NTC1KLYJYz cXBKNTBNDvGc+XHhJt2a6Ln1Jo2Gz1NYl1fkBhyPZXKJa7q3rWjmtFe8n/+FfH+yb53lHT43 reeTcySn35l7Q9wi2jTxXs2TttwVNTNNyuMWRP1lmWsYpJIi+LqkZCtnibHDCzMbTfGQ8klG VyNezvTxUjsr6bBG+IV3gtbuvoXTrxc+8d7zZ9mv5MnW/75mNjqLdEV1eiWe+Hd+r9D8Txc0 bzKXChc/fLVJaymrtkpSnSVrFevBklu2D3+4/7utt+PTgTQup1sZD12DM+OtipI/V4pwnP5c ser9a2mz27ej/5yfdifZbb46zyqbPb0yfj97RHV+fLl59brKxiV6a6ZeOzev6snfOa27pLek 7d3/O45diaU4I9FQi7moOBEAVTa6lMYEAAA= DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20210129052848epcms2p6e5797efd94e6282b76ad9ae6c99e3ab5 References: <88b608e2e133ba7ccd5bb452898848fd@codeaurora.org> <5bd43da52369a56f18867fa18efb3020@codeaurora.org> <20210129052848epcms2p6e5797efd94e6282b76ad9ae6c99e3ab5@epcms2p6> <20210129053005epcms2p323338fbb83459d2786fc0ef92701b147@epcms2p3> <20210208080333epcms2p59403f0acbc9730c9a605d265836a956d@epcms2p5> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> @@ -342,13 +1208,14 @@ void ufshpb_suspend(struct ufs_hba *hba) >>> > struct scsi_device *sdev; >>> > >>> > shost_for_each_device(sdev, hba->host) { >>> > - hpb = sdev->hostdata; >>> > + hpb = ufshpb_get_hpb_data(sdev); >>> > if (!hpb) >>> > continue; >>> > >>> > if (ufshpb_get_state(hpb) != HPB_PRESENT) >>> > continue; >>> > ufshpb_set_state(hpb, HPB_SUSPEND); >>> > + ufshpb_cancel_jobs(hpb); >>> >>> Here may have a dead lock problem - in the case of runtime suspend, >>> when ufshpb_suspend() is invoked, all of hba's children scsi devices >>> are in RPM_SUSPENDED state. When this line tries to cancel a running >>> map work, i.e. when ufshpb_get_map_req() calls below lines, it will >>> be stuck at blk_queue_enter(). >>> >>> req = blk_get_request(hpb->sdev_ufs_lu->request_queue, >>> REQ_OP_SCSI_IN, 0); >>> >>> Please check block layer power management, and see also commit >>> d55d15a33 >>> ("scsi: block: Do not accept any requests while suspended"). >> >> I am agree with your comment. >> How about add BLK_MQ_REQ_NOWAIT flag on blk_get_request() to avoid >> hang? >> > >That won't work - BLK_MQ_REQ_NOWAIT allows one to fast fail from >blk_mq_get_tag(), >but blk_queue_enter() comes before __blk_mq_alloc_request(); > In blk_queue_enter(), BLK_MQ_REQ_NOWAIT flag can make error than wait rpm resume. Please refer following code. int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) { const bool pm = flags & BLK_MQ_REQ_PM; while (true) { bool success = false; rcu_read_lock(); if (percpu_ref_tryget_live(&q->q_usage_counter)) { /* * The code that increments the pm_only counter is * responsible for ensuring that that counter is * globally visible before the queue is unfrozen. */ if ((pm && queue_rpm_status(q) != RPM_SUSPENDED) || !blk_queue_pm_only(q)) { success = true; } else { percpu_ref_put(&q->q_usage_counter); } } rcu_read_unlock(); if (success) return 0; if (flags & BLK_MQ_REQ_NOWAIT) return -EBUSY; <-- out from the function. Thanks, Daejun