Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752022AbdHENx6 (ORCPT ); Sat, 5 Aug 2017 09:53:58 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:45698 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751392AbdHENx5 (ORCPT ); Sat, 5 Aug 2017 09:53:57 -0400 Date: Sat, 5 Aug 2017 06:53:53 -0700 From: Christoph Hellwig To: Hannes Reinecke Cc: Suganath Prabu S , jejb@kernel.org, hch@infradead.org, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, Sathya.Prakash@broadcom.com, kashyap.desai@broadcom.com, linux-kernel@vger.kernel.org, chaitra.basappa@broadcom.com, sreekanth.reddy@broadcom.com, linux-nvme@lists.infradead.org Subject: Re: [PATCH v2 00/13] mpt3sas driver NVMe support: Message-ID: <20170805135353.GA7526@infradead.org> References: <1500038560-11231-1-git-send-email-suganath-prabu.subramani@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.0 (2017-02-23) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 860 Lines: 16 On Wed, Aug 02, 2017 at 10:14:40AM +0200, Hannes Reinecke wrote: > I'm not happy with this approach. > NVMe devices should _not_ appear as SCSI devices; this will just confuse > matters _and_ will be incompatible with 'normal' NVMe devices. > > Rather I would like to see the driver to hook into the existing NVMe > framework (which essentially means to treat the mpt3sas as a weird > NVMe-over-Fabrics HBA), and expose the NVMe devices like any other NVMe HBA. That doesn't make any sense. The devices behind the mpt adapter don't look like NVMe devices at all for the hosts - there are no NVMe commands or queues involved at all, they hide behind the same somewhat leaky scsi abstraction as other devices behind the mpt controller. The only additional leak is that the controller now supports NVMe-like PRPs in additions to its existing two SGL formats.