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 80907C43334 for ; Tue, 5 Jul 2022 08:34:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229652AbiGEIeX (ORCPT ); Tue, 5 Jul 2022 04:34:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229478AbiGEIeX (ORCPT ); Tue, 5 Jul 2022 04:34:23 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA2BA2645; Tue, 5 Jul 2022 01:34:21 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 521C168AA6; Tue, 5 Jul 2022 10:34:16 +0200 (CEST) Date: Tue, 5 Jul 2022 10:34:16 +0200 From: Christoph Hellwig To: Chaitanya Kulkarni Cc: linux-block@vger.kernel.org, linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, axboe@kernel.dk, agk@redhat.com, song@kernel.org, djwong@kernel.org, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, jejb@linux.ibm.com, martin.petersen@oracle.com, viro@zeniv.linux.org.uk, javier@javigon.com, johannes.thumshirn@wdc.com, bvanassche@acm.org, dongli.zhang@oracle.com, ming.lei@redhat.com, willy@infradead.org, jefflexu@linux.alibaba.com, josef@toxicpanda.com, clm@fb.com, dsterba@suse.com, jack@suse.com, tytso@mit.edu, adilger.kernel@dilger.ca, jlayton@kernel.org, idryomov@gmail.com, danil.kipnis@cloud.ionos.com, ebiggers@google.com, jinpu.wang@cloud.ionos.com Subject: Re: [PATCH 1/6] block: add support for REQ_OP_VERIFY Message-ID: <20220705083416.GA19123@lst.de> References: <20220630091406.19624-1-kch@nvidia.com> <20220630091406.19624-2-kch@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220630091406.19624-2-kch@nvidia.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On Thu, Jun 30, 2022 at 02:14:01AM -0700, Chaitanya Kulkarni wrote: > This adds a new block layer operation to offload verifying a range of > LBAs. This support is needed in order to provide file systems and > fabrics, kernel components to offload LBA verification when it is > supported by the hardware controller. In case hardware offloading is > not supported then we provide API to emulate the same. The prominent > example of that is SCSI and NVMe Verify command. We also provide > an emulation of the same operation that can be used in case H/W does > not support verify. This is still useful when block device is remotely > attached e.g. using NVMeOF. What is the point of providing the offload?