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=-2.2 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 2587CC47254 for ; Fri, 1 May 2020 04:35:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08F7920857 for ; Fri, 1 May 2020 04:35:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728118AbgEAEfv (ORCPT ); Fri, 1 May 2020 00:35:51 -0400 Received: from mail-pj1-f66.google.com ([209.85.216.66]:35766 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726153AbgEAEfv (ORCPT ); Fri, 1 May 2020 00:35:51 -0400 Received: by mail-pj1-f66.google.com with SMTP id ms17so1952294pjb.0 for ; Thu, 30 Apr 2020 21:35:50 -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=To43UBG1e+g8aG6khNbixY4ZfPcP8/r1ESfS+GHESdw=; b=UTIMa5x7F/v+G2YzZUFKTr6rufs9051HtKZ/Xfp7lLUApryAx6ga5IbptUS2E5ZN02 hO35ZAWsaN5hex6l9VnuyN/H7w7G48Ann9lEOAsQSRq5ANbZC2gY3LFHqb4X6Ih2nJ56 wOmNJRkt8X5g1LXpPLC02xSQiSVG/rTb4WmXt2VPYd2IgILzhaMyrFge4HNaiMQO/sxh 0vTUaQAZIQ834Fk8c94vMkV7bJrZ2EhcY3FbMa5Git7oVcSVpgZvn8pCQIeiQFjcn5jU hI70kFR+p80OznErkHXi7UNoYsvvlAqj3+tqzcefDFUd5MeB+fq5l+6u9EBA9wOZhbq8 rrHA== X-Gm-Message-State: AGi0PubV71/hZuZmwGWleMA87BwgqB1fUt9FbooerEMc5QYOKorD3546 X1FgksImCcf8IoVvUX8oFUw= X-Google-Smtp-Source: APiQypIw/qn+Lx3WEF4OLo5rnARjH523c2av94Xvc4ZOv22MucXzR1t8G6QYzgJd2NZaLlS/AQxc6g== X-Received: by 2002:a17:902:8e8b:: with SMTP id bg11mr2479431plb.139.1588307750113; Thu, 30 Apr 2020 21:35:50 -0700 (PDT) Received: from ?IPv6:2601:647:4000:d7:6909:5f45:32d1:8e51? ([2601:647:4000:d7:6909:5f45:32d1:8e51]) by smtp.gmail.com with ESMTPSA id p8sm1039804pjd.10.2020.04.30.21.35.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 30 Apr 2020 21:35:48 -0700 (PDT) Subject: Re: [PATCH RFC v3 02/41] scsi: add scsi_{get,put}_reserved_cmd() To: Hannes Reinecke , "Martin K. Petersen" Cc: Christoph Hellwig , James Bottomley , John Garry , Ming Lei , linux-scsi@vger.kernel.org, Hannes Reinecke References: <20200430131904.5847-1-hare@suse.de> <20200430131904.5847-3-hare@suse.de> 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: <831819aa-07b6-ab79-ce08-c6b942510454@acm.org> Date: Thu, 30 Apr 2020 21:35:47 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200430131904.5847-3-hare@suse.de> 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 2020-04-30 06:18, Hannes Reinecke wrote: > +/** > + * scsi_get_reserved_cmd - allocate a SCSI command from reserved tags > + * @sdev: SCSI device from which to allocate the command > + * @data_direction: Data direction for the allocated command > + */ > +struct scsi_cmnd *scsi_get_reserved_cmd(struct scsi_device *sdev, > + int data_direction) > +{ > + struct request *rq; > + struct scsi_cmnd *scmd; > + > + rq = blk_mq_alloc_request(sdev->request_queue, > + data_direction == DMA_TO_DEVICE ? > + REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN | REQ_NOWAIT, > + BLK_MQ_REQ_RESERVED); > + if (IS_ERR(rq)) > + return NULL; > + scmd = blk_mq_rq_to_pdu(rq); > + scmd->request = rq; > + return scmd; > +} Isn't REQ_NOWAIT something the caller should decide about instead of always setting that flag? Additionally, I think some parentheses are missing. I think the compiler will interpret the blk_mq_alloc_request() call as follows, which is probably not what was intended: rq = blk_mq_alloc_request(sdev->request_queue, data_direction == DMA_TO_DEVICE ? REQ_OP_SCSI_OUT : (REQ_OP_SCSI_IN | REQ_NOWAIT), BLK_MQ_REQ_RESERVED); Thanks, Bart.