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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 5D8E1C433E0 for ; Fri, 15 May 2020 19:28:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E9BF2070A for ; Fri, 15 May 2020 19:28:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726188AbgEOT2o (ORCPT ); Fri, 15 May 2020 15:28:44 -0400 Received: from mail-pj1-f65.google.com ([209.85.216.65]:37578 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726144AbgEOT2n (ORCPT ); Fri, 15 May 2020 15:28:43 -0400 Received: by mail-pj1-f65.google.com with SMTP id q9so1414263pjm.2 for ; Fri, 15 May 2020 12:28:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=nZImNymGoYEuV34AxMub5tbECUkkjxtOy1Xv1S4hHgk=; b=R5hWv8erdhc6bjCXyxBsb3tiiJ/JxTzqRXusmEz+vMpsj1/YShm9hENz/gZD/XGPqm cSfXUBL2walAJokOBM6fPjDX2tYTB0yVIH4h1YTHlBZ7RxqJ+0EL5IymtlbOAr5q5fVb yU4fB04Pwci+Vc25IrDIpjSumxaMkLNRKz50k2kmSx9KeAPtRmUQCKeZRlEPYZ7PUcss C/tSt9yMydQZ+0HANCSLZiuBxykkCCJBoFz1cp4wdMmPqW4PG4Wg9Z86YWNPQbwr4aXn XJUQutQv48/X43FQm8byE87SiBErzLk072+QUg2dEwL8QGO/4iH7S78zorQcTmEPLGPi unOA== X-Gm-Message-State: AOAM533HT1MBpbQK8eAEa9rVjcupXE/MJp5RwUJJmp5YIV1cQQv18Ebw BoXq+N353Tti1z0dq2uhso1NRrBl X-Google-Smtp-Source: ABdhPJx63B9aR2blL2MVt2apDb/1DmWG5IwXJZfEZoI9WUJcuqqd48zEfMKlpojViM3FI2aNfrIuZQ== X-Received: by 2002:a17:902:70c2:: with SMTP id l2mr5088540plt.112.1589570921543; Fri, 15 May 2020 12:28:41 -0700 (PDT) Received: from ?IPv6:2601:647:4000:d7:f99a:ee92:9332:42a? ([2601:647:4000:d7:f99a:ee92:9332:42a]) by smtp.gmail.com with ESMTPSA id gv24sm2109345pjb.6.2020.05.15.12.28.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 May 2020 12:28:40 -0700 (PDT) Subject: Re: [PATCH RFC] ufs: Make ufshcd_wait_for_register() sleep instead of busy-waiting To: "Asutosh Das (asd)" , "Martin K . Petersen" , "James E . J . Bottomley" Cc: linux-scsi@vger.kernel.org, Can Guo , Avri Altman , Bean Huo , Alim Akhtar References: <20200507222750.19113-1-bvanassche@acm.org> <198a1467-09db-f846-e153-a9681ff15b71@codeaurora.org> From: Bart Van Assche Autocrypt: addr=bvanassche@acm.org; prefer-encrypt=mutual; keydata= mQENBFSOu4oBCADcRWxVUvkkvRmmwTwIjIJvZOu6wNm+dz5AF4z0FHW2KNZL3oheO3P8UZWr LQOrCfRcK8e/sIs2Y2D3Lg/SL7qqbMehGEYcJptu6mKkywBfoYbtBkVoJ/jQsi2H0vBiiCOy fmxMHIPcYxaJdXxrOG2UO4B60Y/BzE6OrPDT44w4cZA9DH5xialliWU447Bts8TJNa3lZKS1 AvW1ZklbvJfAJJAwzDih35LxU2fcWbmhPa7EO2DCv/LM1B10GBB/oQB5kvlq4aA2PSIWkqz4 3SI5kCPSsygD6wKnbRsvNn2mIACva6VHdm62A7xel5dJRfpQjXj2snd1F/YNoNc66UUTABEB AAG0JEJhcnQgVmFuIEFzc2NoZSA8YnZhbmFzc2NoZUBhY20ub3JnPokBOQQTAQIAIwUCVI67 igIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEHFcPTXFzhAJ8QkH/1AdXblKL65M Y1Zk1bYKnkAb4a98LxCPm/pJBilvci6boefwlBDZ2NZuuYWYgyrehMB5H+q+Kq4P0IBbTqTa jTPAANn62A6jwJ0FnCn6YaM9TZQjM1F7LoDX3v+oAkaoXuq0dQ4hnxQNu792bi6QyVdZUvKc macVFVgfK9n04mL7RzjO3f+X4midKt/s+G+IPr4DGlrq+WH27eDbpUR3aYRk8EgbgGKvQFdD CEBFJi+5ZKOArmJVBSk21RHDpqyz6Vit3rjep7c1SN8s7NhVi9cjkKmMDM7KYhXkWc10lKx2 RTkFI30rkDm4U+JpdAd2+tP3tjGf9AyGGinpzE2XY1K5AQ0EVI67igEIAKiSyd0nECrgz+H5 PcFDGYQpGDMTl8MOPCKw/F3diXPuj2eql4xSbAdbUCJzk2ETif5s3twT2ER8cUTEVOaCEUY3 eOiaFgQ+nGLx4BXqqGewikPJCe+UBjFnH1m2/IFn4T9jPZkV8xlkKmDUqMK5EV9n3eQLkn5g lco+FepTtmbkSCCjd91EfThVbNYpVQ5ZjdBCXN66CKyJDMJ85HVr5rmXG/nqriTh6cv1l1Js T7AFvvPjUPknS6d+BETMhTkbGzoyS+sywEsQAgA+BMCxBH4LvUmHYhpS+W6CiZ3ZMxjO8Hgc ++w1mLeRUvda3i4/U8wDT3SWuHcB3DWlcppECLkAEQEAAYkBHwQYAQIACQUCVI67igIbDAAK CRBxXD01xc4QCZ4dB/0QrnEasxjM0PGeXK5hcZMT9Eo998alUfn5XU0RQDYdwp6/kMEXMdmT oH0F0xB3SQ8WVSXA9rrc4EBvZruWQ+5/zjVrhhfUAx12CzL4oQ9Ro2k45daYaonKTANYG22y //x8dLe2Fv1By4SKGhmzwH87uXxbTJAUxiWIi1np0z3/RDnoVyfmfbbL1DY7zf2hYXLLzsJR mSsED/1nlJ9Oq5fALdNEPgDyPUerqHxcmIub+pF0AzJoYHK5punqpqfGmqPbjxrJLPJfHVKy goMj5DlBMoYqEgpbwdUYkH6QdizJJCur4icy8GUNbisFYABeoJ91pnD4IGei3MTdvINSZI5e Message-ID: <16bb7e00-abbd-060c-c775-ae49a024d7de@acm.org> Date: Fri, 15 May 2020 12:28:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <198a1467-09db-f846-e153-a9681ff15b71@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 2020-05-08 09:27, Asutosh Das (asd) wrote: > On 5/7/2020 3:27 PM, Bart Van Assche wrote: >> The ufshcd_wait_for_register() function either sleeps or spins until the >> specified register has reached the desired value. Busy-waiting is not >> only considered a bad practice but also has a bad impact on energy >> consumption. Always sleep instead of spinning by making sure that all >> ufshcd_wait_for_register() calls happen from a context where it is >> allowed to sleep. The only function call that has to be moved is the >> ufshcd_hba_stop() call in ufshcd_host_reset_and_restore(). >> >> Cc: Can Guo >> Cc: Avri Altman >> Cc: Bean Huo >> Cc: Alim Akhtar >> Cc: Asutosh Das >> Signed-off-by: Bart Van Assche > > Reviewed-by: Asutosh Das Thanks for the review Asutosh. Does anyone else want to review and/or test this patch? Thanks, Bart.