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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 5B341C33CAF for ; Sun, 19 Jan 2020 20:58:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D4B2206D7 for ; Sun, 19 Jan 2020 20:58:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728721AbgASU61 (ORCPT ); Sun, 19 Jan 2020 15:58:27 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:51707 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727556AbgASU61 (ORCPT ); Sun, 19 Jan 2020 15:58:27 -0500 Received: by mail-pj1-f66.google.com with SMTP id d15so5745565pjw.1; Sun, 19 Jan 2020 12:58:27 -0800 (PST) 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=sDRF0S+xxClm8hhrU117sfSXJq23LM47I4S3KoYDs2o=; b=ZsbDSAY4h2ReHyrouj0anoEbSWXXGACuh6Ajuxq+5LbQyrmYCILMoeKkrn73iVKCxu tnIdevfvGjWXKmFuLF0hOEBE2klVWx12qlNWpxXdr+sDbWVcdcNlfIxMSBf8zBje2+cy rC+i6D6YOLWPUnbK1VoeEEqcQFISpIw3+G+MpXugq/ej4y29ncpEBB60wT+TwDb1+2Qx VbHA/DnVejjHXiuvOPvw6Srk3SZbNyoaVjQBVLt1Tsa/MUqIVA57oIa/4VIrN/8HciH3 i1LDmC/VLyWX4YV7h5xzJFBXvX4+j60DtQHCV9Ix22oud3lfNhRSIemQSYv0ysWs85f6 yhsA== X-Gm-Message-State: APjAAAVEaJPoRZEntqLnl9r+uku9/JJ5zsESAc4x8zDnTmXbSH6o+v6R HEoO788xp/Ee9q9pVtDweCtK2Zq3 X-Google-Smtp-Source: APXvYqx2MQ2Kiu0RvlhV4RdMSj3W4nMMbUVec6HjWSvK+LhwrqLu9rWnBbLib9yCrZPzcu/UwqNovA== X-Received: by 2002:a17:902:7296:: with SMTP id d22mr11942628pll.55.1579467506627; Sun, 19 Jan 2020 12:58:26 -0800 (PST) Received: from ?IPv6:2601:647:4000:d7:781f:ca33:6085:f83a? ([2601:647:4000:d7:781f:ca33:6085:f83a]) by smtp.gmail.com with ESMTPSA id b19sm35718450pfo.56.2020.01.19.12.58.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 19 Jan 2020 12:58:25 -0800 (PST) Subject: Re: [PATCH 5/6] scsi: core: don't limit per-LUN queue depth for SSD when HBA needs To: Ming Lei , James Bottomley , linux-scsi@vger.kernel.org, "Martin K . Petersen" Cc: linux-block@vger.kernel.org, Jens Axboe , Sathya Prakash , Chaitra P B , Suganath Prabu Subramani , Kashyap Desai , Sumit Saxena , Shivasharan S , "Ewan D . Milne" , Christoph Hellwig , Hannes Reinecke , Bart Van Assche References: <20200119071432.18558-1-ming.lei@redhat.com> <20200119071432.18558-6-ming.lei@redhat.com> 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: <5a467267-e990-45d1-4b69-18d8c0cd17b3@acm.org> Date: Sun, 19 Jan 2020 12:58:24 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200119071432.18558-6-ming.lei@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2020-01-18 23:14, Ming Lei wrote: > +static inline bool scsi_bypass_device_busy(struct scsi_device *sdev) > +{ > + struct Scsi_Host *shost = sdev->host; > + > + if (!shost->hostt->no_device_queue_for_ssd) > + return false; > + > + return blk_queue_nonrot(sdev->request_queue); > +} In other words, sdev->device_busy is maintained for all SCSI devices except for those SSDs controlled by a SCSI LLD driver that has no_device_queue_for_ssd set in its host template. I'd like to see different behavior, namely that sdev->device_busy is not maintained for any SSD except if that SSD really needs the sdev->device_busy counter. The blacklist mechanism may be more appropriate to mark such SSDs than the SCSI host template. What I also noticed is that most scsi_bypass_device_busy() calls have an exclamation mark (!) in front of these calls. I think that inverting the return value and renaming this function into e.g. scsi_maintain_device_busy() would result in code that is easier to read. Thanks, Bart.