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 CFC0DC433EF for ; Thu, 3 Feb 2022 22:53:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355899AbiBCWxh (ORCPT ); Thu, 3 Feb 2022 17:53:37 -0500 Received: from mailout2.w2.samsung.com ([211.189.100.12]:48802 "EHLO mailout2.w2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241561AbiBCWxg (ORCPT ); Thu, 3 Feb 2022 17:53:36 -0500 Received: from uscas1p2.samsung.com (unknown [182.198.245.207]) by mailout2.w2.samsung.com (KnoxPortal) with ESMTP id 20220203225335usoutp0262d19d5493a26b0a4c1ffc024bdcfd37~QaIwmwB3Q1807918079usoutp02E; Thu, 3 Feb 2022 22:53:35 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.w2.samsung.com 20220203225335usoutp0262d19d5493a26b0a4c1ffc024bdcfd37~QaIwmwB3Q1807918079usoutp02E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1643928815; bh=P8iFln1vTh31HniSBbBfkrPb5ufwoscktLN/SPSvqtU=; h=From:To:CC:Subject:Date:In-Reply-To:References:From; b=kBoDDV7N3IWTsJg18SoFSKrC1dKOSdhiESaQXs19kU9Og0dHecHqXM4gFpEYQTVF2 Uy33O2mEp3wp3jYch8aG5fa6UH1xMESpvkFj3S0h1fQTHqCscCBELkG9ww3WJoCqgw Cqf0fn035dp1fxRTFHM5MR/eVOPgC5CjRiyECkbI= Received: from ussmges2new.samsung.com (u111.gpu85.samsung.co.kr [203.254.195.111]) by uscas1p1.samsung.com (KnoxPortal) with ESMTP id 20220203225334uscas1p1549c0f1a4417c55925d56f53cbff11c6~QaIwb8ss40411504115uscas1p10; Thu, 3 Feb 2022 22:53:34 +0000 (GMT) Received: from uscas1p1.samsung.com ( [182.198.245.206]) by ussmges2new.samsung.com (USCPEMTA) with SMTP id DC.33.10104.EEC5CF16; Thu, 3 Feb 2022 17:53:34 -0500 (EST) Received: from ussmgxs3new.samsung.com (u92.gpu85.samsung.co.kr [203.254.195.92]) by uscas1p2.samsung.com (KnoxPortal) with ESMTP id 20220203225334uscas1p2cb08fa69376935551d792df32e67acdc~QaIwHlPgw1507515075uscas1p2L; Thu, 3 Feb 2022 22:53:34 +0000 (GMT) X-AuditID: cbfec36f-315ff70000002778-d5-61fc5ceecc28 Received: from SSI-EX3.ssi.samsung.com ( [105.128.2.146]) by ussmgxs3new.samsung.com (USCPEXMTA) with SMTP id CF.C7.09657.EEC5CF16; Thu, 3 Feb 2022 17:53:34 -0500 (EST) Received: from SSI-EX3.ssi.samsung.com (105.128.2.228) by SSI-EX3.ssi.samsung.com (105.128.2.228) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.1.2242.4; Thu, 3 Feb 2022 14:52:43 -0800 Received: from SSI-EX3.ssi.samsung.com ([fe80::8d80:5816:c578:8c36]) by SSI-EX3.ssi.samsung.com ([fe80::8d80:5816:c578:8c36%3]) with mapi id 15.01.2242.008; Thu, 3 Feb 2022 14:52:43 -0800 From: Adam Manzanares To: Mikulas Patocka , "joshi.k@samsung.com" CC: Luis Chamberlain , Christoph Hellwig , Keith Busch , Vincent Fu , =?iso-8859-1?Q?Javier_Gonz=E1lez?= , Chaitanya Kulkarni , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "dm-devel@redhat.com" , "linux-nvme@lists.infradead.org" , linux-fsdevel , Jens Axboe , "msnitzer@redhat.com >> msnitzer@redhat.com" , "Bart Van Assche" , "martin.petersen@oracle.com >> Martin K. Petersen" , "roland@purestorage.com" , Hannes Reinecke , "Frederick.Knight@netapp.com" , "zach.brown@ni.com" , "osandov@fb.com" , "lsf-pc@lists.linux-foundation.org" , "djwong@kernel.org" , "josef@toxicpanda.com" , "clm@fb.com" , "dsterba@suse.com" , "tytso@mit.edu" , "jack@suse.com" , Kanchan Joshi Subject: Re: [RFC PATCH 3/3] nvme: add the "debug" host driver Thread-Topic: [RFC PATCH 3/3] nvme: add the "debug" host driver Thread-Index: AQHYF5o0LMwUDmubDUu2kNRmd7lMHKyAS6yAgAI7QoCAAAKFAIAAN5GAgAAXUoCAACBXAA== Date: Thu, 3 Feb 2022 22:52:43 +0000 Message-ID: <20220203225336.GA255651@bgt-140510-bm01> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [105.128.2.176] x-exchange-save: DSA Content-Type: text/plain; charset="iso-8859-1" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected X-Brightmail-Tracker: H4sIAAAAAAAAA02Se0xbdRTH+d1e7r3UMC8dwk+qWSRuJrJ1g4zltwXR6BJvNEsWwWl0zl7h jvGeLWyiRpnNCA8ZFIGVIo8ij61sA8scz46U7iHrRkoqa61DhgMU2MpjSnl0IOV2Sf/7nN/5 npPPSX6UQGQgQqjEtAxOlsamhBJC/MqN/wZ2OA672F3KqQjUPFxEoPLZJQGaMTzwRSVFKhJZ xjYhvaPSF5kXT2HogW4NQz11JRg633wdQ383/QRQnsmMIddoOCrpuwuQ3h6GevT9OKppHCdR gbWDQFen9QLUdHMVQ7bicYCUuUMYGlC7CGT8cwhHzS6ETn+/RKKp3iNviBnLb+8ySoWDZBS1 93DGcieT0WnzCKat/lvmB1sTYLp/zyaY725fFzCq+X8Jxnq7HWMKFQ6CmRu348yV0UKSmbk6 RDAtl4fwg5s/EkbFcymJJzjZzmip8FiraoI83rbpC2NFbDY480w+8KMgvRuWrozgbhbR5wEc UezLB8J1Po1Bw6km8mno1p12gm9cBPDeTAPJF7MAVmobfPmiF0BdTvXGLoLeBVdu/ixwcyD9 IVxeegjcIQHdIoTKkuH1BkVtpqOhZukdPvM6nDfWefKH4NzgAuZmnH4ZmgbqN9796UiYm79M uNmP/hguducCNwM6CDpvXdjIC+hgaB+rwXjtAFhX2SPgOQiudo0SPL8ER5yTntMC4SXnI4Kf lUBbWamHo+G1ajXOcxhs1Ex7HAJgf8UYzs8+Dw3nbLj7Lkh3CuHQ2VrP0v0wt2DCw2J49oLF E9ICWLqQQ/JFG4CqZTNWDLaqvczVXiZqLxO1l4nay6QW+GpBcKZcnprAySPSuJMSOZsqz0xL kMSlp+rA+i83rRrTO4DVPifpAxgF+gCkBKGB/snlK6zIP57N+pKTpX8qy0zh5H1ATOGhwf6N ia2siE5gM7hkjjvOyZ52McovJBuLjQlSpTum11RvTz58K8llLeNqtAWRP65JfYzF1+5HxQ1C S75ov2vn3b+6qt5/MrzyR1GcdSqpxejaF/h1PR6y5x9D1x770Vi5Jexx9GDZJ7LX4j+LujSc bE/Ip2K3Sqdnm1UHzL0VzrYAaaTm8Ij4m3bJ0kJDmOIxrqnISjxJdt04GBH3XusrJoe4aU05 Mdm57YhOvmgu7f+qKJmazPklcuJo2a9odvuhKkP2cLh6PrWq27L38z6Ge1F/ZvdzSWqyfHt1 TENKkoR9MtjSmfwo5uKJFY3UxzbvvJ9h2jLT8ewLfuIcbUDClvbqrBBHuKuQ/cB67nLmYljv mz5ReTu27Q3F5cfY8FcFMjn7P9xzj6VUBAAA X-Brightmail-Tracker: H4sIAAAAAAAAA02Se0xTVxzHOffe3l66lF0e2qMsbkPnomydjRseE8bcHzN3YxnLNGoUcVe5 gY6HpOWhhggbSqDTYnEQLDgfENhgQSkIhmdoNaQUHFJLa6c4B1XbanlsrrYgTGiX9L/P73e+ j3OSQ+FhDt5qSpqZzcky2fQoUkBIC7Hy912J8+wmzZM1qOl+GYkqpz04muqf4KHysio+Mk6G oB5XNQ+NvPgeQxOaRQx1Xy7H0K9NNzH0uKEWoFLDCIbmH0pQuXYMoB5rNOru0RPoQr2Nj340 XydRr7MHRw0DCxiynLEBpCoxYeiWep5EunETgZrmETp5ysNHjr6kbZGM8U48oypy8Zmii/cI xjicw2gaS0mmta6AOWtpAEzX3UKS+WHoJs5Uzf5DMuahDow5XeQimRmblWDaH57mM1O9JpK5 0mYivg7fK4hN5tKluZzsg7hvBalXqx7xs1pDjujO7SwEytcUIJiC9IdwcLiDVAABFUY3Adg4 ovQP0wDerXHyfEMfgPano2DJQtKb4NxAC77EEfQe6PU8BUsinL4igMNazysHRYXTcfCS5wuf 5hM4q7vs1++CM7f/xZaYoNdBw6265b2Q/giWKLz+ZgsBHSfmlkXB9D74oqtkuRjQK6F78Lfl PU6LoHXyAuZ7Aw3run/HfbwC2icWeD5+Gz5w2/k+joDN7mekzyuGloqf/BwHb/ysJnwcDesv Of0XCoX6c5OEz7sK9v9iIc6AVeqAanVAlDogSh0QpQ6Iugh4jUCUI5dnpByRb87k8sRyNkOe k5kiPnQ4QwNefUfDgi7xOhi3zoi1AKOAFkAKj4oQplXOsWHCZPboMU52+IAsJ52Ta0EkRUSJ hMx+1YEwOoXN5tI4LouT/X+KUcGrCzGJQLrrTlW+yptvt2DiLt1W8bir5USxM9m++JL3+sag HddWCvftOJorquWfjxQFrSh451nIaGS95Bi2ffdiHF7T2XbyjVMP4iscurJiRXOf+3mewBi7 Jzyk4qDnU7P3c5HdEbP9+Ft2c/ys8hvbQedC22dK6XjzVJKhseDjG2uPC6uzi3NDzR36BCKo c0uo/X5a6mgpZw3+S1KqbMkzTT3WxE8btf2sXihOfw89iWXa16zbOxB9L2tg7Or5GPfm9Rm1 I7xHb24ZJFs3PH9Xsk1m0Fd+t9aWwM9W4kFbE7xj1VlDiV+9PFQXS+ljFAl/sI6df7f3bvgz SZXP3a6hvuyMIuSprGQjLpOz/wEQteiU/QMAAA== X-CMS-MailID: 20220203225334uscas1p2cb08fa69376935551d792df32e67acdc CMS-TYPE: 301P X-CMS-RootMailID: 20220201183359uscas1p2d7e48dc4cafed3df60c304a06f2323cd References: <20220201102122.4okwj2gipjbvuyux@mpHalley-2> <20220202060154.GA120951@bgt-140510-bm01> <20220203160633.rdwovqoxlbr3nu5u@garbanzo> <20220203161534.GA15366@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Feb 03, 2022 at 03:57:55PM -0500, Mikulas Patocka wrote: >=20 >=20 > On Thu, 3 Feb 2022, Luis Chamberlain wrote: >=20 > > On Thu, Feb 03, 2022 at 05:15:34PM +0100, Christoph Hellwig wrote: > > > On Thu, Feb 03, 2022 at 08:06:33AM -0800, Luis Chamberlain wrote: > > > > On Wed, Feb 02, 2022 at 06:01:13AM +0000, Adam Manzanares wrote: > > > > > BTW I think having the target code be able to implement simple co= py without=20 > > > > > moving data over the fabric would be a great way of showing off t= he command. > > > >=20 > > > > Do you mean this should be implemented instead as a fabrics backend > > > > instead because fabrics already instantiates and creates a virtual > > > > nvme device? And so this would mean less code? > > >=20 > > > It would be a lot less code. In fact I don't think we need any new c= ode > > > at all. Just using nvme-loop on top of null_blk or brd should be all > > > that is needed. > >=20 > > Mikulas, > >=20 > > That begs the question why add this instead of using null_blk with > > nvme-loop? > >=20 > > Luis >=20 > I think that nvme-debug (the patch 3) doesn't have to be added to the=20 > kernel. >=20 > Nvme-debug was an old student project that was canceled. I used it becaus= e=20 > it was very easy to add copy offload functionality to it - adding this=20 > capability took just one function with 43 lines of code (nvme_debug_copy)= . > BTW Kanchan's group has looked at adding copy offload support to the target= . I'll let him respond on the timing of upstreaming, I'm under the assumption that it is also a relatively small patch to the target code. > I don't know if someone is interested in continuing the development of=20 > nvme-debug. If yes, I can continue the development, if not, we can just=20 > drop it. >=20 > Mikulas > =