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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 13B08C2B9F4 for ; Wed, 23 Jun 2021 01:35:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8A9661361 for ; Wed, 23 Jun 2021 01:35:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230175AbhFWBhY (ORCPT ); Tue, 22 Jun 2021 21:37:24 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:36540 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229775AbhFWBhW (ORCPT ); Tue, 22 Jun 2021 21:37:22 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1624412105; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=+4WX1+XKSVWz3RW6iMyqFbDGyD0cNV+UYK/Z+DXHS7M=; b=L34xrZXUG+0sH4QR0i9Bp/LGyjT1tabswLs2FDUGqcHKhPOeNstnrMJGvFPHIXywZuqtcHR2 dqHIX4JT2H7jARe9VrPWvELjCe4FD0L8Os4BNrGYDIl3wmnL6l6AKRMXIfuLZn+MIwrkadTH jCKCZo78KZhxfpcpJXVEGGEXQiQ= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n06.prod.us-west-2.postgun.com with SMTP id 60d28fb3638039e9977d6deb (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 23 Jun 2021 01:34:43 GMT Sender: cang=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 349A9C4360C; Wed, 23 Jun 2021 01:34:43 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: cang) by smtp.codeaurora.org (Postfix) with ESMTPSA id 5974CC433F1; Wed, 23 Jun 2021 01:34:42 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 23 Jun 2021 09:34:42 +0800 From: Can Guo To: Bart Van Assche Cc: asutoshd@codeaurora.org, nguyenb@codeaurora.org, hongwus@codeaurora.org, ziqichen@codeaurora.org, linux-scsi@vger.kernel.org, kernel-team@android.com, Alim Akhtar , Avri Altman , "James E.J. Bottomley" , "Martin K. Petersen" , Stanley Chu , Bean Huo , Jaegeuk Kim , open list Subject: Re: [PATCH v3 8/9] scsi: ufs: Update the fast abort path in ufshcd_abort() for PM requests In-Reply-To: <2fa53602-8968-09e4-60f4-28462d85ae08@acm.org> References: <1623300218-9454-1-git-send-email-cang@codeaurora.org> <1623300218-9454-9-git-send-email-cang@codeaurora.org> <16f5bd448c7ae1a45fcb23133391aa3f@codeaurora.org> <926d8c4a-0fbf-a973-188a-b10c9acaa444@acm.org> <75527f0ba5d315d6edbf800a2ddcf8c7@codeaurora.org> <8b27b0cc-ae16-173a-bd6f-0321a6aba01c@acm.org> <3fce15502c2742a4388817538eb4db97@codeaurora.org> <8aae95071b9ab3c0a3cab91d1ae138e1@codeaurora.org> <0081ad7c-8a15-62bb-0e6a-82552aab5309@acm.org> <8eadb2f2e30804faf23c9c71e5724d08@codeaurora.org> <2fa53602-8968-09e4-60f4-28462d85ae08@acm.org> Message-ID: <386c2e650232d7a900f5c1bbf98bd5a5@codeaurora.org> X-Sender: cang@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bart, On 2021-06-17 01:55, Bart Van Assche wrote: > On 6/16/21 1:47 AM, Can Guo wrote: >> On 2021-06-16 12:40, Bart Van Assche wrote: >>> On 6/15/21 9:00 PM, Can Guo wrote: >>>> 2. And say we want SCSI layer to resubmit PM requests to prevent >>>> suspend/resume fail, we should keep retrying the PM requests (so >>>> long as error handler can recover everything successfully), >>>> meaning we should give them unlimited retries (which I think is a >>>> bad idea), otherwise (if they have zero retries or limited >>>> retries), in extreme conditions, what may happen is that error >>>> handler can recover everything successfully every time, but all >>>> these retries (say 3) still time out, which block the power >>>> management for too long (retries * 60 seconds) and, most >>>> important, when the last retry times out, scsi layer will >>>> anyways complete the PM request (even we return DID_IMM_RETRY), >>>> then we end up same - suspend/resume shall run concurrently with >>>> error handler and we couldn't recover saved PM errors. >>> >>> Hmm ... it is not clear to me why this behavior is considered a >>> problem? >> >> To me, task abort to PM requests does not worth being treated so >> differently, after all suspend/resume may fail due to any kinds of >> UFS errors (as I've explained so many times). My idea is to let PM >> requests fast fail (60 seconds has passed, a broken device maybe, we >> have reason to fail it since it is just a passthrough req) and >> schedule UFS error handler, UFS error handler shall proceed after >> suspend/resume fails out then start to recover everything in a safe >> environment. Is this way not working? > Hi Can, > > Thank you for the clarification. As you probably know the power > management subsystem serializes runtime power management (RPM) and > system suspend callbacks. I was concerned about the consequences of a > failed RPM transition on system suspend and resume. Having taken a > closer look at the UFS driver, I see that failed RPM transitions do not > require special handling in the system suspend or resume callbacks. In > other words, I'm fine with the approach of failing PM requests fast. > Thank you for your time and efforts spent on this series, I will upload next version to address your previous comments (hope I can convince Trilok to pick these up). Thanks, Can Guo. > Bart.