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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B46DFC6FD1C for ; Fri, 24 Mar 2023 19:45:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231859AbjCXTpM (ORCPT ); Fri, 24 Mar 2023 15:45:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231725AbjCXTpL (ORCPT ); Fri, 24 Mar 2023 15:45:11 -0400 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AC236191; Fri, 24 Mar 2023 12:45:11 -0700 (PDT) Received: by mail-pj1-f41.google.com with SMTP id qe8-20020a17090b4f8800b0023f07253a2cso2646651pjb.3; Fri, 24 Mar 2023 12:45:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679687110; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=mzEyCZHLH4Zfj5DYk4naroNB2YGbHeAPk3MJAB81cn0=; b=yXz+9p/Qy/Tq7riURNiqm2h2hiOP1jYAfB94Y+iHlVKve4R5aQUQ+6zYppamjldXdA XG1NA3P76rmv+wWJXCeRTmYrgC0tdKht6HTjl1y7v4ntqlTWjFj7qIGDQu2KIvRW97hk Pe4E6WtjHL1xuQRpJGKTe7cTho/drgWKGT1U2sQGmb0vu9/gDE3ozkLNltM3cDW7x3H9 8rAFEX7W/04Lag5zPpKCXh311NNUe02dwdRzEhuu2jvgAQxUyDhhnCNsDugjImNw6H2H nTtzc6mC+wSrIl0ZyNXOAAIxvnsuVi+HAi6vnJeSYSz4OGrERgCNCc0AWtwE1yX3+riq nTEw== X-Gm-Message-State: AO0yUKUYnzwt98uDVrM/PEKR/Sp0JPWAsdvCavyaxSC8tXnQADG2ta5A Wg3i55nX+EENAYUn1BtuXlE= X-Google-Smtp-Source: AK7set+WBcQsEOXCQ/txqOh9eErFNTaYEWF2xegD7KrWmJzmFiNv92WvD5FLTUar7NcICYJm6jYnKg== X-Received: by 2002:a05:6a20:7a98:b0:cc:868f:37b3 with SMTP id u24-20020a056a207a9800b000cc868f37b3mr3618846pzh.58.1679687110519; Fri, 24 Mar 2023 12:45:10 -0700 (PDT) Received: from ?IPV6:2620:15c:211:201:386d:2249:7df8:ecf? ([2620:15c:211:201:386d:2249:7df8:ecf]) by smtp.gmail.com with ESMTPSA id a14-20020a62e20e000000b00625d84a0194sm14306035pfi.107.2023.03.24.12.45.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Mar 2023 12:45:09 -0700 (PDT) Message-ID: <0dfa3352-cdca-90c1-a6c9-ea4a4c85dfa1@acm.org> Date: Fri, 24 Mar 2023 12:45:07 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v5 01/18] block: Add PR callouts for read keys and reservation Content-Language: en-US To: Mike Christie , hch@lst.de, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, james.bottomley@hansenpartnership.com, linux-block@vger.kernel.org, dm-devel@redhat.com, snitzer@kernel.org, axboe@kernel.dk, linux-nvme@lists.infradead.org, chaitanyak@nvidia.com, kbusch@kernel.org, target-devel@vger.kernel.org Cc: Chaitanya Kulkarni References: <20230324181741.13908-1-michael.christie@oracle.com> <20230324181741.13908-2-michael.christie@oracle.com> From: Bart Van Assche In-Reply-To: <20230324181741.13908-2-michael.christie@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 3/24/23 11:17, Mike Christie wrote: > Add callouts for reading keys and reservations. This allows LIO to support > the READ_KEYS and READ_RESERVATION commands and will allow dm-multipath > to optimize it's error handling so it can check if it's getting an error > because there's an existing reservation or if we need to retry different > paths. > > Note: This only initially adds the struct definitions in the kernel as I'm > not sure if we wanted to export the interface to userspace yet. read_keys > and read_reservation are exactly what dm-multipath and LIO need, but for a > userspace interface we may want something like SCSI's READ_FULL_STATUS and > NVMe's report reservation commands. Those are overkill for dm/LIO and > READ_FULL_STATUS is sometimes broken for SCSI devices. Reviewed-by: Bart Van Assche